T4→T5 train is short time

I check how many gem I need when I train troops, and compared between "new(0 to T5)" and "upgrade(like t4 to t4)".

the amount of gem is the same as the "time" for train.

this is the result.

in total,  "t4 → t5" is much faster than "t1 → t4".  I mean.... like this↓

so,  if you have many t4 troops,  "t4->t5" is easy way to get many point in some event.