Welcome to TBN.
I'm also at the 50 hour mark on my LX4900, but haven't had the chance to do it yet.....the only thing I can add is what my dealer told me....which is if the hydro oil looks good, you don't need to change it, which is contrary to what the manual says. He said change all other fluids and all filters...U will have to add a bit of hydro oil from changing the filter.