Yeah, I think we're saying the same thing but I can't tell either. I'm pretty sure you understand everything, on the off chance though, I'll try to reword it.
Grants stop once you put in $36,000, provided you do the $2500/year method, $7200 total in CESG. Thats my target for RESP contributions.
"Re; catch-up years, I think I've confirmed that you can claim the full $2500/yr/child, it's just the current year that I need to account for the contributions in the other plan"
this part is where I'm confused. In 2018, 2019 and 2020, how much money are you putting into your RESP (all accounts) each year? Assuming you have always deposited $1600/year (since the child was age 0) the answer should be $3,400/year for this year and the next two years. If that's the case, we're on the same page.
To be clear, looking at a calendar, your child should have 18 annual contributions. That includes age 0, some people forget age 0 is a contribution year. That will be 15*1600 plus 3*3400 which is $34,200
Its better then you think. If your child is 15 and you started the pool plan 14 years ago, did you skip contributions in their birth year? You can catch up for the birth year and deposit $5000 this year and receive $1000 in grants (for 2018 and 2003).
I want to make sure we agree, this is important to me (I value education, hopefully your kid becomes a doctor and treats me when I'm old). The big issues are what happened in the birth year and how much are you putting in this year in total? This might require a spreadsheet to avoid confusions.
I think you'll end up contributing $35,800 out of the max grant matching $36,000 for child 1, missing $40 in grants (pretty much perfect). Child 2 will max out CESG.