upper limit for train buff ?

this is the note about how long it takes for T5 troop training by using buff,  and check if there is upper limit.

I misunderstand the display of gem is equal to the train time + cost of resource.

but as for below 2500gem,  the display of gem does not change as time change.

■how long does it take to train 2000 T5 troop?

■no buff 

1d 17:40  / 2800gem

■15%

rune train+15%

1d 14:05:43 / 2500gem

■25%

rune tran +15%

duke train +10%

1d 12:02:10 / 2500gem (time is small but gem is the same compared to above 15%)

■35%

rune tran +15%

duke train +10%

kingdom buff train + 10%

1d 10:11:17 / 2376gem

■22000 T5 troop?

■no buff

TODO

■15%

rune train+15%

■25%

rune tran +15%

duke train +10%

■35%

rune tran +15%

duke train +10%

kingdom buff train + 10%