Kohler....the very people that designed and manufactured this engine... are quite adamant that straight grade 30 weight detergent based motor oil be used in all Kohler K and M Series engines when the ambient temps are above 32 F.
Using multi-grade oils promotes increased oil consumption, as you already understand.
High oil consumption comes down to one or more of these problem.
1. oil is leaking out of the engine oil pan/block assembly.
2. oil is being burnt in the combustion chamber due to worn rings, worn valve guides or both.
3. oil is being forced out due to a problem with the crankcase ventilation system.
Oil being burnt as part of the combustion process should be easy to detect in the form of a bluish tinge to the exhaust smoke.
The other two problems should show up as oil dripping on the ground when the machine is parked for awhile.
There is obviously a problem that needs to be diagnosed and corrected because if the oil level gets too low, then you will break the rod. There is no alternative oil that will correct any of these problems. A Leak Down Test is in order if there are no visible signs of oil loss.