I have never heard of a commercial "VFT mix"..
Is this something you bought at a store that actually says its supposed to be for VFT's?
If so, I wouldn't trust it..it could be anything.
Its best to make your own mix..
Opinions vary on the ideal mix..
some like perlite and sand in their mix, thats fine..but personally I dont use either..
I have tried all the different mixes over the years!
A peat with sand mix was far too heavy and dense for me..and I absolutely hate perlite..
its ugly, floats to the surface, and serves no useful purpose I can see..I will never use it again.
My VFT and Sarr mix has settled on pure peat for most of the pot, with a top-dressing of LFS..
I go two seasons between repottings..(but three is too long!)
The LFS on the top is mainly to prevent the peat from splashing around in the rain..keeps things neat and tidy.
Noddy, im curious what your "VFT mix that doesn't seem like a VFT mix" is..
can you elaborate?
Scot