Season average ratings

I think it's widely acknowledged that central MF have difficulty in achieving ratings on a par with most other positions. The end of the season is approaching for me and I currently have four CM, which are summarised as follows:

21/6*, average 6.3 from 26 matches, 5 goals, 2 assists
22/5*, average 6.4 from 29 matches, 5 goals, 1 assist
25/4*, average 6.7 from 22 matches, 2 goals, 1 assist
29/3* (Free kicks SQ), average 6.7 from 28 matches, 6 goals, 2 assists

Weirdly they seem to rate better the lower skilled they are, I don't let the 3* take FK often btw. The 21 year old is quite highly valued, but has always struggled to get any kind of decent ratings consistently and his contract is up at the end of the season. The 22 year old I've always felt has been slightly better, just struggles for consistency. The two older MF are relatively consistent I would say.

My DMCs are as follows:

25/5*, average 6.2 from 14 matches (also DMR)
20/4*, average 7.0 from 35 matches (also DC)

I usually play with a three man MF with one holding player. My team is fairly good for my level (despite me not investing really in the close season), should make top four in my league, got to SF of CL. What I was wondering is how does this compare to the 'average' for MF, is very hard to benchmark them against the rest of my team?

Nobody has any feedback then before I sell my entire MF?

Well, I will give an answer. (I consider 7 an ok rating for midfielder)
My midfielders:Attachment 23926
What I do on my team (and is for either DMC or MC) is when I first get the player, point are added to the attributes to be all even, then I look at which skills I want that are highest, def or off, and then add to that and physical.

This works for me, I play a variety of formations and orders but mostly press whole pitch, sometimes they get arrows.
best MC:
Attachment 23925

I had trimmed back my squad so I didn't really think posting numbers would help. Most of my team are 5* or recently gained 6*.

I'm only second season so I can't give info with much authority.

My central midfielders rate about 0.5-1.0 on average lower than the more consistent def and st (AMs are the glory hunters and rate highest) - the 2 CMs I have left at the moment are 6.7 & 7.1 ave after a pretty average season with my fair share of losses. But I mostly play on the flanks and my cms seem more likely to pick up bookings (naming them Graeme Souness and Billy Bremner might be the reason for bookings). Red and Yellow cards might have hurt their ratings recently. When they rate 7s or more my team is usually performing well - 6s and it depends if I'm lucky in front of goal, 5s and I've probably lost or they're off the park.

I can't comment with much experience on skill point allocation (so probably ignore this) but for CMs I'm going to try roughly balancing all ave stats since they play more a passing & def role in my team and so are expected to be all-rounders. I think I allowed my CMs def to lag a bit too much.