Simple Q&A Pathfinder (By RAW) I

[Keneth]

A71 There is indeed nothing that stops you selecting the Limbs evolution multiple times. While each of these limbs may be used to wield a weapon, you must however remember that all the penalties for wielding multiple weapons apply. To counter these you should select Multiweapon Fighting.

I know but it's a bit ridiculous that your eidolon can get an arbitrary amount of attacks per round at -4 penalty with MWF as long as it has enough evolution points to get more arms. There should be some kind of limit.