Broadband renewal - adding to bill

[AH99]

My current contract is due for renewal at the end of May but I've been invited to renew and the deals aren't too bad at the moment,  but when I add the product I want (same as I'm on at the moment) I am told it will "add to" my bill.   Does anyone know if it'll replace what I am paying at the moment or it will add another £37 to my current bill until May?

Thank you

[Adam+sky+82]

Hi, The new contract would replace the older contract