Your engine will seize before you finish cutting the grass.
Seriously, considering that most people either never change the oil (just do top-ups) or use off-brand or possibly unsuitable oils, I think your engine will last a good long time on your mix.
Should be fine. I like to run 0W30 Castrol with the same filter in my Kohler. Most of the small engine oils sold by Kohler etc. are SJ. And I believe they are non-resource conserving as well.
My translation (which could be wrong)- the preferred oils for these air cooled engines are not low HTHS and contain higher percentages of certain anti-wear additives than are allowed in most of the xW30 oils currently marketed in the US.
Well, it made it through one mow so far - still running!
The 5W30 was Chevron & 15W40 was Delo...I'll change it again this time next year....maybe. I keep hoping the Simplicity will blow up so I can get a Deere!...lol...