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