Of course you can just call CRA to discuss and normally CRA will ask you to either adjust or just send them T2202A and they will adjust for you.
Because credits should be claimed according to the order, so if you claimed credits such as medical, transfer of spouse’s credits, etc in 2010 and 2011. , then such credits would be either reduced or even not used and your tuition credits should be applied first. So to have an accurate amount, suggest to adjust 2010 and 2011, unless your 2010 and 2011 situation is quite simple.
Because credits should be claimed according to the order, so if you claimed credits such as medical, transfer of spouse’s credits, etc in 2010 and 2011. , then such credits would be either reduced or even not used and your tuition credits should be applied first. So to have an accurate amount, suggest to adjust 2010 and 2011, unless your 2010 and 2011 situation is quite simple.