Spectra voltage drop at motor

[discovery]

I have a older Catalina 300 and I'm struggling with a issue...I recently changed my membrane and prior to this change my product was about 175ppm .Now that the membrane is changed I'm getting 260ppm my analog pressure gauge is reading about 70 and it's symetric..I have in the past replaced the wiring back to the spectra unit with the accumulator..sensors and the mag came pump and motor...this wire is now 4 gauge for a 25 foot run to battery's...I have a 30 amp breaker between the battery and the unit. I have a 3 yr old pro con 140 gph vane feed pump..but I have found these items

1. There is a 1/2-3/4 voltage drop at the breakers battery side to the output side..
2. When the motor is running the voltage at the motor itself that is connected to the breaker from my battery bank
Is 1/2- 3/4 lower than the buss bar..

So if I'm showing 13.5 at my battery monitor
I'm getting 12.9 or so at the output of my water maker breaker...then 12.6 or so at the buss bar next to the feed pump box..then 12 or 11.9 at the motor...I'm sure I would get better production if the motor was seeing 13 instead of 12...but I'm going direct from the battery with 2 gauge to the breaker and 4 gauge to the bus..and then the smaller supplied spectra wiring.

Is it possible the breaker is worn and that's why I'm losing 1/2 volt?

Could there be a issue inside the spectra assembly?

Or is it normal to have a reading of 11.9 at the motor while operating when you have a 13.5 voltage reading at your batteries?

Thanks for reading

Tried to reach out to JT with emails and texts and vm