Tuition Loan amount isnt enough

I get the full maintenance grant and loan as my household income is below £15,000 but my tuition loan is saying i am only entitled to £3,465 when my current course is £8,250 i am going into my second year and i had to pay for my first years tuition as i had previously done 2 years foundation degree somewhere else i understand that student finance only give you 4 years of finance, but why would this affect my tuition if ive paid for one of my years myself.