I am in the exact same situation, Giselle78 so I totally understand. If you have hair to trim, then you definitely aren't stuck at MBL. You probably would have been WL and beyond a long time ago without this current issue (I think we started LHCF around the same time). I also think Kami (former feature of the month) discussed a similar issue when she was MBL and striving for WL.
I only have 2 inches to WL but I keep cutting that same 2 inches over and over because the ends don't always look so hot. I'm starting to think that maybe I'm expecting perfection, when in reality, I know that hair doesn't always grow at the same speed, nor is it the same texture throughout. The texture differences don't bother me until an underprocessed section reaches the ends. This is when I start noticing less than perfect ends.
BostonMaria posted a link yesterday from a lady who has kneelength hair and she describes how she grew her hair to knee length first, THEN she started trimming to "thicken her ends up." I believe Chicora talks about this too.
I prefer to reach WL with full, healthy ends, but I might have to give this method a try. I never have because I've heard the whole "cut splits before they travel up the length" talk for years now. In my case, I don't necessarily have splits, but underprocessed hair that doesn't lay down as smooth as my fully relaxed hair. Even after a corrective, the texture is different.
After recently trimming two inches in one section, I realized that I'll be encountering the problem again in about 6 months, because further up the strand, it's underprocesed again.
I'm tired of the madness! In the meantime, I will continue bunning, rollersetting, avoidiing direct heat, moisturizing, etc. Most importantly, I'll continue to thank the Lord for what I have because it's the longest that it's ever been in my life.
You'll make your length goal, Gisselle78. Don't give up!
I was gonna say exactly this. It's like, try staying at SL, now that's bad 
