Although your answer may be closer to the truth, this paper suggests using a fixed number not divisible by 1 or 5. So, for example, 6 minutes and 23 seconds.

The paper doesn't make any claims regarding interval or ranges whatsoever, only single values.

To replace that with saying 383.512 seconds would signal confidence in the time of a future event, but not in a speaker who is scheduling a meeting with another human.

383.512 is divisible by one, the answer is 383.512 ... :)

But its hard to extend this one to prices and bids. If you give a range of money, people will come back and say "but you said you could do it for [the lowest possible number you gave]"

The answer is to make it clear what the tradeoffs are. For example it could be more cash and less stock. Or lower price but longer lead time. Just offering a range without any other variables would be foolish, and complicated negotiations usually have more factors than just price.