why does the pennzoil synthetic blend have higher pour and pump points than the straight pennzoil? is the blend better for extended drains? say in the 5-6000 mile range? or is it a wash? just curious. i've used mobil1 for years. i broke in my current car on valvoline durablend, then put in mobil1 with supersyn, but i doubt i'm going to stick with it, so i'm reading all the spec sheets for the major brands. thanks!