Check Valve Question

Recently got into kegging and have been reading up on the subject. It seems check valves are highly recommended and it makes sense why especially if using a splitter/manifold. I have a double co2 regulator and a 3-way manifold connected to one of the outputs. Both outputs on the regulator have ball check valves and Midwest tells me that the manifold itself has a check valve on each shut off.

When I was searching on the subject some people recommend using another check valve (a common choice 64048) between the manifold and each keg. Is the extra check valve really necessary? I know it doesn't cost much but I would prefer not cut the lines and put it in if I don't need to.

Just wondering if some people had experience with the a manifold with ball check valves and how well they work. Mine specifically is the three way brew logic from Midwest, but other experiences would be nice as well.

Shouldn't need to add any extra check valves. The check valve on the output will prevent higher-pressure CO2 from leaving the line to the keg, and if the CO2 can't go anywhere, beer can't get in the line.