Problem with counting double-sided cards on lists cover

I have problem with lists covers (picture below), and double-facing cards (ex. Tergrid, God of fright). I have list with 28 cards but on list cover I see 35 (I think its an error in counting double sided cards)

I have same error when I have lists with full art cards (Modern Horizon Art Series). I have 114 cards on the list but on cover I see 166.