I would agree with you. But I am not a rep with LS or an engineer. I'm sure you'll be fine with 5w-40 full synthetic at the 50hr service. However, this might be a way to void your warranty should anything blow up. But without an oil test, good luck seeing the difference when the oil is drained. Just tell your dealer that's what your going with and if he will still honor warranty work.
Did the change today. used Chevron 5-40 full Syn. Picked Chevron, as they are partners with GS Caltex which is the Company that LS says to use. (and on sale at Wally's for $12 a gallon) So 1/2 way agreed with LS.
The filters were unbeliable. oil and HST were put on with super glue by superman. Reg Hyd came right off. Glad that you and other warned about dumping hyd fluid when you pull the HST filter. Also had the threaded part that the oil filter screws to be the piece that came loose not the filter. Thats nuts. LS really needs to not put filters on the way they do. If those filters came off the way they should, this would be a really simple job, instead of using huge channel locks and a chain wrench.
Thanks so much for all your input and answering my questions!!!