Actually, the website scoring changed late last month and the apps score the same way now.
https://www.chess.com/blog/News/chess-com-dev-update-april-28-2017
Edit: just read your note. The old site won't have the change.
Is the Tactics scoring different when you do it through the APP vs. web browswer
Sort:
I find that the most your rating can go up and down is + or - 9 when using Chess.com through a web browser.
I've recently started doing tactics on my ipad through the Chess.com app and I've found that I get more points (like +15 or so) when I do a tactics puzzle correctly/quickly.
Note: in my browser I use the "oldchess.com" so perhaps that has something to do with the difference in scoring?