Probably.
See, if the killing of a unit which triggers the creation of another, it doesn't matter how many combats your units survive, because ANY time they win, a new unit is created.
Which means: On a higher difficulty level, there are fewer units created, but as your units have a worse chance to survive, it's still balanced...
or at least should be...
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"Am Anfang war das Wort" - J.W. Goethe, "Faust"
"So they've learned from me" - Napoleon
Bonaparte, during the Battle of Leipzig