SV pulse lasers are Ultra Effective against shields, so they’re doing 100x damage, while CV fixed pulse lasers are only Very Effective, so they only do 10x damage (although there are more of them and the base damage per minute is much higher, so the discrepancy in damage is less than 10x).
For CVs, pulse laser turrets are the shield breakers - they are also Ultra Effective and their base damage (per minute) is much higher than SV pulse lasers.
I’m not sure why Rex decided not to make CV fixed lasers Ultra Effective against shields like all other PLs are, but I’m pretty sure that’s why you’re getting those results.
Testing with Pulse turrets are not that effective either, something akin to .5% dmg to shield, when they hit. To be more effective their speed needs to greatly increase. Also tested this scenario, it wasn’t that great to be honest, kinda left me underwhelmed. What left me unbalanced is the fact that half the pulse lasers were twice as effective for less than half the amount of ammo expended.