To the original question, mixing dino and synthetic is ok with any brand if you NEED to. It does dilute the synthetic, so it will negate some of the advantage of 100% synthetic.
I can't see saving $6-8 on a filter even if the manual says it's ok. They don't seem to give a reason for that thinking. I'd especially want a new filter on a nearly new engine too, which may have metal filings in the filter.
A shop giving a 40% sale for motorcycle Mobil1 that sells it on sale for $7, first marked it up nearly 60% over retail..lol.
After break in, I went with Shell Rotella Syn, but then learned it isn't a true synthetic. Next time around I put in auto Mobil1 15-50, because it doesn't have the friction modifiers, and also has a higher zinc and phosphorous content that's been lowered for the energy conserving weight oil.
I am nervous about this weight tho, and I do use my bike in cold weather. I may change the weight, or go back to Rotella or maybe even the BIKE specific Mobil1 if I can find it easily.
Mobil's own site says: Additive packages balanced differently for motorcycle engine and transmission operation. For passenger vehicles, fuel economy and emission system protection are higher priorities. These require low phosphorus systems and the use of friction modifiers. Motorcycle oils do not require friction modifiers for fuel economy and for better clutch friction less/no friction modifier is optimum. Motorcycle oils allow the use of higher levels of antiwear additives such as ZDDP (phosphorous).
Reading that, you could easily say, well I'll just use the higher weight Mobil1 WITHOUT friction modifiers.
On the other hand, reading Mobil1's spec page for comparing ZDDP levels for the different weight oils, it shows the BIKE oil has 1600ppm ZDDP, the 15-50 has 1200ppm, and the energy conserving type has 800ppm. Reading this, it would seem there is more than a slight difference between the Bike oil and the 15-50.
Mobil's spec page:
http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf