Not only are the time to temps different, they are astronomically inaccurate.
I once had a multi hour time to temp for a 3° temp drop. Like huh? Really?
I am wondering how does the T-stat derive these numbers? Is it a learning T-stat that bases the time estimate on previous performance run times for similar temp ranges? Otherwise it would need to know the cubic footage and layout of my living space as well as the type and tonage of my HVAC unit. Is it some mathematical derivation of my time zone and local climate? Who knows?
But, perhaps I ponder too much. I ignore the times because they are useless to me. I just wait for it to do my bidding and provide me with unending glorious environmental comfort.