Compare three supplier quotes without being fooled by the headline price

Dan asked which quote is cheapest. Before answering, work out what "cheapest" can mean here. Lowest price per user? Lowest monthly bill? Lowest total you're committed to? These give different answers when one contract is 24 months and the others are 36.

So the real task is a fair comparison: every quote on the same VAT basis, every compulsory charge included, costs shown both per month and over the contract, and the gaps turned into questions. Which supplier to choose is Dan and Priya's decision. Your job is to make sure they're comparing the right numbers.

Partly. AI is good at pulling figures and conditions out of several documents into one table, and at spotting clauses you might skim past. It's unreliable at arithmetic done in its head, and it has no idea which differences matter to Fernway.

Use it to extract and lay out. Do or check every sum yourself.

Real supplier quotes are commercially sensitive. Some are marked confidential, and pricing shared with you in a tender isn't something the supplier expects to end up in a tool outside your organisation's control. There's usually little personal data, maybe a sales contact's name and email.

Use a tool your organisation has approved for work documents, signed in with your work account. If the quote is marked confidential and your organisation hasn't approved any AI tool for that kind of material, do the comparison by hand. You can remove the contact names without losing anything useful.

The fictional practice files are safe to use anywhere. Your organisation's policy and approved tools still take priority.

Give the AI the whole quote, including the terms, never just the summary page. In this set, the VAT basis for quote B and its compulsory support fee are both in the small print.

Tell it what Fernway actually needs (40 users, 12 handsets, two sites). Without that, it can't work out handset costs or spot that "standard sites" might not cover the depot.

If the quotes are PDFs, check the text came through: tables in PDFs sometimes paste as a jumble. The CSV version of this exercise avoids that. Its first line is a label saying the data is fictional; if you open it in a spreadsheet, delete that line so the column headings are read as headings.

Any of the general assistants can build the table from pasted or uploaded quotes. The difference that matters is how the sums get done.

Notice what the better version leaves out: no role-play, no long preamble. Every sentence closes off a specific way the comparison could go wrong.

I need to compare the three supplier quotes below for [what you're buying]. Our requirement: [e.g. 40 users, 12 desk handsets, two sites].

Using only the text of the quotes, including the terms, build a table with one column per supplier showing: contract length, monthly charges, any compulsory extra charges from the terms, one-off charges for our requirement, total cost over the contract and average cost per month.

State each quote's VAT basis and convert everything to include VAT at 20%. Show your working for every total. Where a quote is unclear or silent on something we need, don't assume: list it as a question to ask that supplier. Don't recommend a supplier.

[paste quotes]

This is the kind of answer the weak instruction can produce. It reads well, and its conclusion is wrong.

Before you check any number, look at what's missing: no handsets, no support fee, no mention of VAT, and a recommendation you didn't ask for.

Other things to check:

• Brackenmoor's £17,880 is correct (£480 × 36 = £17,280, plus £600). Check it anyway: a right answer you haven't checked is luck.
• "More flexibility" ignores that Pellow Hart renews automatically for 12 months unless you give 60 days' notice.
• Quillfield's "included for standard sites" has been read as "free". The Midlands depot may not be a standard site.

Send one follow-up that names the specific problems, then check the arithmetic yourself.

Please redo the table. Pellow Hart's terms 2.1 say its prices exclude VAT, and terms 9.4 add compulsory Premium Support at £45 a month for more than 25 users. Include 12 desk handsets for each supplier. Show every total as a line of working. Add a row showing what Pellow Hart would cost over 36 months if it renewed for 12 months at the same monthly charges, and label that row as an assumption. Remove the recommendation.

Then check each line with a calculator. Every figure below has been worked through by hand; if your AI's numbers differ, trust the calculator and find where it slipped.

• Quote A: £12.00 × 40 = £480.00 a month. £480.00 × 36 = £17,280.00, plus £600.00 = £17,880.00. Divided by 36 = £496.67 a month.
• Quote B: service £10.50 × 40 = £420.00, plus 20% VAT = £504.00. Support £45.00 plus VAT = £54.00. Monthly total £558.00. £558.00 × 24 = £13,392.00. One-offs: implementation £750.00 plus VAT = £900.00; handsets 12 × £80.00 = £960.00 plus VAT = £1,152.00. Total £15,444.00. Divided by 24 = £643.50 a month.
• Quote C: £13.20 × 40 = £528.00 a month. £528.00 × 36 = £19,008.00, plus handsets 12 × £95.00 = £1,140.00. Total £20,148.00. Divided by 36 = £559.67 a month.

Partly. The AI was quick at the part people find tedious: reading three sets of terms and pulling out the clauses that matter. The follow-up surfaced the notice periods and price-increase clause in seconds.

It saved nothing on the arithmetic. You had to check every sum, and the first version was so wrong that a quick glance would have sent Dan the wrong answer. If you'd trusted it, AI would have cost Fernway money.