I have a gallon and a half, thereabouts, of Meg's APC+. I love it! I also found out the hard way that the 'little' foam component of that product can cause staining issues if and when used on paint if it isn't rinsed thoroughly...and I mean super-duper-dyan-whoppin' thorough. Don't ask me how I know. LOL!!! Even when highly diluted and rinsed about 10 million minutes, it still can linger. Luckily for me polishing removed the stain. Nothing like hot water rinsing, if you ask me, when it comes to getting rid of residual soap and suds. I don't have a hot water rinse supply, so simple soap is all I use anymore...better yet, rinseless products.
The APC did not dry (heck, I had a rinse hose in hand), was agitated, then rinsed, and rinsed, and rinsed. Don't think it's so? I've had the bad luck on sand colored paint, and black was the worst.
Had a similar incident happen with Optimum Power Clean via their recommendations and to my dismay. Luckily that to polished out. Kleen Strip Prep-All and ISP wouldn't touch it. Took M67 to polish it out. Mike Phillips was the guy who told me it should polish out. Luckily his experience paid off big time for me with that issue. He did not recommend any particular polish. I used what was closest to my hand, which was M67, a marine one-step compound and polish.
So, with that, if I use APC on paint anymore it will be at a far more diluted rate that anyone has ever suggested I use.