Welcome to Business Logic. This is where I'd really like pushback to result in things that aren't edgecases.
However you also run into day to day business issues like:
* What if it's now a Holiday and things are closed?
* What if it's some commonly busy time like winter break? (Not quite a single holiday)
* What if a disaster of somekind (even just a burst waterpipe) halts operations in an unplanned way?
Usually flexability needs to be built in. It can be fine to 'target' +3 months, but specify it as something like +3m(-0d:+2w) (so, add '3 months' ignoring the day of month, clamp dom to a valid value, allow 0 days before or 14 days after),
However you also run into day to day business issues like:
* What if it's now a Holiday and things are closed?
* What if it's some commonly busy time like winter break? (Not quite a single holiday)
* What if a disaster of somekind (even just a burst waterpipe) halts operations in an unplanned way?
Usually flexability needs to be built in. It can be fine to 'target' +3 months, but specify it as something like +3m(-0d:+2w) (so, add '3 months' ignoring the day of month, clamp dom to a valid value, allow 0 days before or 14 days after),