Yes, they can have a set of rules to set the prices. But then it’s not that different from the current system, which really is not problematic in the first place. I know this is the place for pedantic nit picking, but the fact that prices have some granularity is very much a non-issue.

In any case, actually probably have such rules, just not public. I am sure they have sales people being paid full time to agonise over such issues.