Well up until two weeks ago I was in the same quandary, my car was on variable service, but IÂ’d prefer fixed, so I had the car serviced at 7400 miles which was exactly one year from when I bought it, while it was in the dealers, I had them set it to fixed service schedule.
A personal thing, but I didnÂ’t like the idea of going for nearly 20K on the same oil.