My previous OCI was almost 2 years and a little over 7000 km and the OLM was at 40%, with 5w30 GM Conventional with an AC Delco filter. I changed it in mid May with QSUD 5w30 and a Fram TG filter. OLM was reset to 99%. I have only driven in the city doing short runs, once in awhile on the 4 lane for no more than 15 km. I have less than 400 ( four hundred )km on it and the OLM has gone to 94%. It is my first time using any Synthetic oil. This seems a little excessive to me. Any thoughts ?