The amount in box C is the same amount as the amount in box 14 of your T4. TurboTax automatically pulls the amount from your T4 so you don't have to re-enter it on your RL-1.
Hello, In my case, I have received two separate T4, and one T1.
So the box C in R1 does not match the value that turbotax is presenting me and I am unable to edit it.
After contacting support via help, it appears to be a bug in the application, box C should be editable.
Employer sent me two T4s and one R1.
The workaround:
Added the first T4 without a R1, and leaving the T4 field referenced in the R1 box C empty (EI contribution).
On the second T4/R1, on the T4 field added the first T4 field value to it to get the same total of box C of R1.
then when entering the R1, the values matched.
you may just have to ignore the errors at the end of your process for those fields.