Performer

The changelog for E+ 1.67fix2 includes:

You can now give instruments to any pet that has the Performing skill.

Does this make any difference to the results of an ensemble?

I've noticed that sometimes I can do two Ensemble actions in a row from full stamina, but sometimes I'll become exhausted on the second attempt. I decided to do some experiments where I payed close attention:

Experiment #1: First ensemble cost 59 stamina (138 sp to 79 sp), second ensemble cost 36 stamina (79 sp to 36 sp).

Experiment #2: First ensemble cost 54 stamina (138 sp to 84 sp), second ensemble cost 58 stamina (84 sp to 26 sp).

Does the stamina cost vary according to how much reward you get, or something?

(I'm playing Elona+ 1.61 with the Custom mod)