jeejz thats crap.
1)have they only changed the censors? maybe there is a dodgy wire or so?
2)you topped up the oil, i hope between those 2 lines on your oil meter stick?
during right handers.... could be because the bottom is in an angle, so when your in a right hander, it can be that there isnt any oil for a short time. thats not to bad, i think most 550's have that. i think its updated in the 575, not sure dough.
i hope i helped you, good luck with it anyway, im 16 years old, and im studying engines for about 2 years now. these are just the ideas i can come up with.
ps: the slow down light is very common on the 550.