Can i use more of the tuition credits to reduce amount owing to zero. Calculations within turbo tax only use a certain amount and then want to carry forward the rest

After running all the slips T4s, T2202, turbo tax does a calculation to use an amount to reduce the taxes. It also has a small amount to transfer to a parent.  Why can I not increase the credit instead of carrying forward?  and why can I not get this transfer to carry onto my return?  It does not link and wont accept the manual entry.