Almost every support call about "the wholesale price is not applying" is this: the customer was given a price level, but the account is still configured to take the retail price, so the level is recorded and ignored. Or the account is set correctly and the customer was never assigned a level. Check both before assuming anything is broken.
Once both are set, the same product carries several prices and the right one is chosen by who is buying - walk-in retail, small wholesale, large wholesale - without a cashier having to remember or key it manually. Removing that manual step is most of the value, because a price a cashier types from memory is a price that is sometimes wrong.
Keep the number of levels small. Four is workable. Once you are running a dozen bespoke prices, nobody can audit whether a customer is being charged correctly, and the system stops being the thing that protects your margin.