Yes LM only has semi synthetic in this grade, synthetic would just offer better drain interval and slightly better oil film life.
10W-40 MoS2 is something i.e. nearly like a fully synthetic oil(sharing all good properties of synthetics). LM cant be compared with Zic, shell, caltex etc.. its such a good quality blend of oil that already the drain intervals are pretty high
Imho.. use a semi synthetic, drain it on time and thats it!
What we are talking ebt right now is similar to comparing which one is better? A carnauba car wax? or a synthetic? Or a hybrid?
For eg:
Check 10w-40 MoS2 semi synthetic vs 0w-40 fully synthetic




Notice that the synthetic is just slightly better for fuel econo, poorer in friction prevention and wear tear, better in deposit prevention, oil film strength and resistance to ageing.
And thats exactly what iv been telling... dont go for the fancy of synthetic! It might sound cool but lower viscosities aren't what our small engines need... they are poorer for wear and tear prevention... we are not talking about V8s.. 6ltr engines, its just a poorly built 1.3 or 1.6ltr engine...
They do need some greasing!