Not sticking up for lumber liquidators but go online click on customer care click on flooring 101 pick a topic hardwood collection pick a style say dura wood and complete instructions are their confusing maybe but there if any further questions ask Bob who is a certified inspector with nwfa and all other entities.
Inspected 2,000 sf Australian Cypress builder used osb over concrete, nailing schedule 8" to 14" gaps wide enough to see the space between the tongue and groove this was a 3/4" solid 4 7/8" wide. Squeaking, moving, spacing between subfloor and hardwood same with osb and concrete. But had he read further he would have realized they only recommend 18 guage cleats to fasten their exotics. This was blamed on seasonal gaps according to him. Some short boards did not even have a fastener at all. Measurements of the wood did not bear this out. 'This was new construction. And the only cause was inappropriate installation. I have installed carpet, vinyl and hardwood but my experience, at least in El Paso Texas is that many installers fail because they fail to read the manufacture's guidelines as regardless of what we know they do the guaranteeing and their guidelines must be followed. I agree wholeheartedly regarding LL better be sure what you are dealing with as they cover their butts pretty good. Ha Ha read the requirements for their warranties and what they will do for you if it is wrong. How does a store credit sound?

Moisture differences for 2 1/4" solid are 4%, solid plank 2% according to their website instructions. Which are also NWFA guidelines.

Jim, I wasn't aware that using OSB over concrete is a recommended practice. I thought you could only use 3/4 ply initially.