Ah, yeah, and CE + CE != CE in theory.
In practice, if you use a pre-certified module, and you keep the power levels down, you could skip the entire RF testing (for CE, not FCC). It really depends on the equipment, and doing the testing anyway might be cheaper.
RED might even be skipped, it is applicable to higher power transmitters.
My point is, first step you need to identify which standards are applicable, needs testing, etc.
Write down on a paper, do a planning, get a signature from your boss, that these are the only tests that need to happen and only stuff I need to comply with. Do this as the first step of the project.