not that any LBS would ever do this of course - but hypothetically...
Suppose you are buying a £950 pound bike and £50 of accessories (helmet/lights/safety-related clothing/whatever). Total £1000.
I can imagine a situation where the bike could get discounted to 800, and the accessories were overpriced to 200. Same total. Makes no difference, does it?
Until you remember that the “final payment” is a percentage of the “bike price”, not the “bike + accessories” price...
I did hear rumour of someone who paid £200 for a pump.....
not that any LBS would ever do this of course