filter differential and the PLC

I suck at theoretical math.

I have a bank of six filters

Four to tank one (5 Hp pump motor)
One each for the next two tanks (3 Hp each)

I have pressure sensor (0-30 psi) on either side of each filter generating a 4-20 mA signal

Would the formula (f1 + f2) / 2 = filter differential pressure be accurate.

Thank you for your time and attention.

(YES I tried Wikipedia, gave me a head ache)

f2 - f1 would be differential pressure. (f1 + f2) / 2 would be average pressure

Awe nice

You just killed three lines of code X 6

Knew I was overthinking this

Thank you kindly Okie