Did you check the team's whose stadium it was usual TP's?
I was the 'home' team [or the one on the left in the game fixture] in last season's Inter Cup. I checked the grounds usual TP's, adjusted my TP for the InterCup accordingly to what I thought I should set it at, I got a full stadium - 17,900 -
In actual fact the ground I played at, had their TP set at 16, I set my price at 21 and still got a full crowd. Its actually in my 'ALL TIME RECORDS' in Peaky Blinders FC stats - 17,900 - when my ground is only 10,000 capacity.