Online FLR FP help needed

[emmz13]

Hey peeps,
My hubby is about to submit his 3rd FLR FP application (2nd extension) and when directed to the IHS payment page it states that he is applying for FLR (M) which he isn’t. He has called the information line and has been told that it’s all the same so don’t worry and that the case worker will assess him for whichever visa he is best suited. Tbh we should have switched immediately after his first visa was granted but we didn’t have the money. Our last application in 2017 we were eligible for FLR M but no one changed us over so I don’t understand what’s going on.
We are 5 years in to our 10 year partner route so switching now is pointless but it seems we don’t have a choice. Our concern is that should our circumstances change over the next 2 1/2 years and we are no longer eligible for FLR M will we have to restart FLR FP or can we switch back for our last 2 1/2 years?
I am a carer for my mum so we are currently financially exempt but we do have a combined income of over £18,600 but working for a supermarket hours vary greatly month to month.
The last thing we want is to start all over again, I was diagnosed with cancer last year and that is enough of a shadow over my head without this, I just want to get to the point where my hubby has ILR so that our children will have some stability in their lives.
Thanks in advance!!