I'm sorry, I know this has probably been done to death but in about 2 hours I'm getting an "Interim" oil change at the shop by my work. My bike is only 350k into it's break in, but I'm doing it now because I have a 1000k trek coming up next week and thought better safe than sorry. The shop suggested using semi-synthetic oil (with some confidence). I thought this was a no no during the break in period? Is this still the case or does it matter much these days? Thanks.