Continuity mistake: In the restaurant (of Mark and Stacy's date), the upper cabinets in the back by the left corner of the screen are not covered by curtains. Then when Damone comes in and gives Mark the wallet, the same cabinets are now covered. Then seconds later as Mark and Stacy start leaving, they are uncovered again.
Continuity mistake: In the beginning when they're all showing up for school Eric Stoltz is putting his skateboard in his locker. A couple of minutes later he and his friends are getting out of the van with his skateboard.
Audio problem: After Spicoli crashes Jefferson's car, Jefferson's brother says "My brother's gonna kill us - he's gonna kill us" yet his mouth isn't moving during those lines (even though shown from the back you can still tell). Then camera faces him and he now matches the words.
Continuity mistake: When Rat approaches Stacy at the check-out to ask for her phone number, the characters in the background keep changing. Sometimes you see Damone standing there; other times there are different people.
Answer: From what I can gather, "So Much in Love" by Timothy B. Schmit was in the original release of the film, but due to licensing rights issues, home video and cable TV versions of the film replaced this and two or three other tracks. For the 1999 DVD release, the rights seem to have been renewed and the soundtrack matches the original theatrical release.