I have a lovely chrome M4-P. At close distances the RF is in perfect alignment, however at middle and far distances it's clearly out on the vertical alignment. I spoke to one tech who told me that it could be easily aligned for close or far but not both. That's kind of frustrating because even though it's still quite easy to focus, the alignment issue is annoying.
It is an easy job but the tech you spoke to should be avoided. I'm not saying you should do it yourself but here is an excellent demonstration on an M6 which is just an M4-P with a meter