[Suggestion] Amortized cost option

[DaveFromTheInternat]

Right now, cost seems to be calculated based on "I paid X for the printer and expect it to work for Y minutes (or hours, or seconds, or...), and that's going to be a constant for cost calculation until I change Y" (which is an entirely reasonable way of doing it, and definitely should be the default).

It'd be nice (for those of us who have to justify our hobby expenses) to have the option for an amortized cost also shown. "I paid X for the printer, I've spent Y minutes printing so far, this job is estimated to take Z minutes, so my cost per minute of print time is going to be X / (Y + Z)". The first print will report as amazingly expensive (cost of printer + cost of filament + cost of power), but price will come down rapidly as you use the printer, so later prints will be much cheaper than earlier prints, and I can explain "yes, I did pay a lot for the printer, but I used it a lot, and now it works out to only being a pittance".