Tire Rotation/balance - Questions

Hello,

I have a some noobie questions for the forum re: proper approach to tire rotation and balancing. I have a 2007 Camry LE 4-cyl. The owners manual appears to recommend same-side rotation (i.e., front to rear/rear to front, always on same side) (picture only, no text, so I assume that's what they mean!)

1. Does that mean that two tires will always stay on the drivers side and two on the passengers side? i.e., they'll never be put on the opposite side, not even after already rotating once on one side?

2. Recently when I had my all season rubber taken off rims and winter rubber put on, the mechanic mistakenly switched drivers front to passenger front (and vice versa) and driver rear to passenger rear (and vice versa). I had the tires marked properly to guide the switch, but the mechanic messed up. If the Toyota direction noted above is indeed that tires should be front-rear switch and never switch sides, how big a deal is this mechanic's mistake? I'll be keeping the winters on for around 3,500 miles (bringing their total wear to around 7,000 miles on front - albeit once on drivers front once on passengers front but last two rotations on front). Going back for another appointment is a pain so I'd do it only if it could cause significant mechanical issue. I assume it's not?

3. Re: rotation pattern, do I follow tire manufacturer recommendation or car manufacturer (if conflicting direction)? Same question for frequency of rotation/miles/km?

4. My tires get rotated and balanced whenever I change rubber (not rims) for all-seasons/winters. Some places offer to rotate (whole tire/on-rim) when I get an oil change - I assume balancing is only needed when rubber changes on rim?

Thanks!