2015 my DRW was delivered to me with 4,000 miles on it or so. I towed til the next summer then back to MORryde, that added another 4k or so. Later that fall with at least another 4k I raised up the RV and checked the bearing play doing the push/pull on the user edge of the tires. The play was well within spec. So I had a friend spin one tire at a time while I pumped the grease into the EZ Lube ZERK as fast as I could stopping to wipe the old grease off as it came out. I stopped once the fresh grease started coming out.
I did the above because I didn't trust the grease or how well it was greased.
Until a person actually uses the system they really don't know.