Um, yes; that's the issue, since that's not what the card says it does. Currently, the description is:
Wall: -70
Attack: N
N = wall lost
In that game I didn't lose 70 wall; I lost 16, so it should only have done 16 damage.
If it was supposed to do 70 damage every time, then it would just be;
Wall: -70
Attack: 70
So either the description or the code for it needs fixing.
Edit(2 hours later): I only just figured out this probably should have been in the Development section; I was thinking of Development as for new stuff, and Support as for bugs and maintenance. Sorry!