Well, to be cear, I was suggestng you add the SeaFoam before you do the flush, so it can tidy things up inside & put any deposits it can remove, into suspension in the old dirty fluid, before you flush the system with new fluid.

That way any removed deposits will come out with the old dirty fluid.

If you add the new fluid & SeaFoam to a unclean system, the new fluid will dirty up right away!!!!

BTW, I first pinched the return line shut, then removed it at the cooler, unpinched it & drained the pumps reservoir into a catch bucket, then plugged the return line with a golf tee & topped off the pump reservoir with new flush fluid.

Then I routed a piece of scrap hose from the cooler into my catch bucket .

During the flush/pump out, I found it easier to control the fluid level in the P/S pump reservoir & thus prevent getting air in the system from low fluid levels, by removing the pumps drive belt & spinning it's drive shaft with a variable speed drill motor.

Trying to do it with the engine at idle, pumped the fluid out faster than I could pour it in, so I got a lot of air in my fluid the first time.

With the variable speed drill motor driving things, you can slow down the pump out rate & keep the reservoirs level up enough to prevent getting any air in the system.

My Taurus system was plenty dirty, so I used about 3 qts to flush it & get it squeeky cleen inside!!!! lol

Just some additional thoughts for consideation.

Let us now how it goes.