After having used my ID Poncho tarp about a half dozen nights, always pitched a-frame between two trees, I'm noticing some damage/wear on the seams. This is actually my second tarp, I exchanged the first after noticing this problem, but I'm concerned that it happening a second time indicates that it's my doing. I certainly don't think that I've been over tightening my lines, though I do use cord tighteners.
MEC's return policy is pretty generous, but I would feel bad returning/exchanging this again if I'm totally at fault. So I'm wondering if this is typical for these tarps and whether it's worth trying to repair/reinforce, and whether I may have caused this by over tightening.
Pictures:

Typical pitch:


