Chrony's are a great tool and I always use one when shooting if possible. That being said, most chrony's on the market are not precision instruments. One will vary from another. I haven't used a CED M2
yet, but it's next on my list.
In another thread, I said I wouldn't use ES's generated by a chrony to select or reject a load and that's the way I feel for the most part. I prefer a good sampling of data on a particular load combined with actual groups sizes at ranges of 300 yds and more to make a load choice.
A chrony can give me good ball park info and take a lot of guess work out but actuall shooting tells me the overall performance and decides what velocity and BC to use for drops.
Welcome to LRH and good shooting,