6* player training speed drops?

[Siddharth Shanker Singh]

I've seen people on here mention that once a player gains 6* his training speed drops, is that right? So am I doing the right thing by saving SP on my 5* (1 SP from 6*) player untill the last day of the season? Do I add SP on the last day of this season or on the first day of new season?

A player Training Speed drops as he gains a NEW STAR...But the Speed Drop is much more significant when he becomes a 6 star......