I own a PS3 and PC, I have ps3 hooked to a cellular modem while PC hooked to a land

[Adstellarum]

is there a way I can not have my account locked out each time I may want to switch from one to the other, and there are reasons why I wish to have my PS3 on a cellular modem and PC on a land line cable connection, and the reason I bought the PC version recently is because on the PS 3 it is much harder to select the target I wish to select, now this isn't a problem in normal instances but once I start hitting those raids like Bahamut's Coil and beyond I imagine playing on PC will give me faster reaction time

[Radunas]

Is there no way for you to use a router to use both on your cable modem? You say there are reasons why you need/have to have it setup this way, why? A router would enable both to be played on from the same IP, which is why I imagine they lock you out, for ATO (account takeover) or other fraud.

[Adstellarum]

because there are times that the cable modem line gets heavily used and therefore increases ping dramatically

[worldofneil]

is there a way I can not have my account locked out each time I may want to switch from one to the other

Yes, add an authenticator to your account (either software or hardware). From my own experience as well as what other forum people have said, it suggests that once you have an authenticator on your account it ignores the IP check (since anyone needing to login as you would need that security token). That's the only known way to not hit it all the time.