Is there a reason why should I use flametal shield over carapace buckler if I prefer to parry?

[Chicken]

Since flametal is a round shield not a buckler it got lower parry bonus or the more block power made up for it?

[Raiden]

Carapace is better for parry.

[Bdeslaurs]

for some reason the flamemetal shield lvl 1 has less block force than the carapace shield lvl 1. I don't see why we should waste flamemetal on it and not just keep using a high level carapace shield. I hope it's just an oversight.