Our dynasty group has a separate “repeat pot” for teams that win back to back. Is this normal or atypical?

My 12 team dynasty league is $120 buy in every season, with $100 from each player going to 1st/2nd and the additional $20 going to the “repeat pot.” The punishment for finishing dead last is to add $50 to the repeat pot at the end of the season. So, this side pot grows $290 a season until someone wins 2 years in a row and they cash it out.

My question for the community is, is this a normal practice or is my league unique in doing this? I, personally, love this because it really incentivizes building a dynasty.