to be pedantic, and yet correct.... there is no tolerance of -5+10 on a slot. this is a common misconception.
the bible on slots is the eurocontrol basic cfmu handbook. section 4 page 4-7 refers
it states quite clearly that for airline operators, they need to coordinate the departure time to comply with the slot i.e. slot time/ctot minus taxitime equals pushback time.fullstop.
the 15 minute window is designed for atc, and atc alone to " optimise the departure sequence "
pilots seem to think that this is their bit of leeway, and can get quite possesive of something that is patantly not theirs!
a little education can go a long way!
