How do I sum between check boxes in google sheets?

I have a google sheet file that I'm using to collect data from boss drops in a game. Every once in awhile there is special loot. That special loot comes on average every 867,000 points. What I'm trying to do in the sheet is create a way to see how many points it has been since I received a special loot. A cell called "points dry".

The easy way is to just manually sum the points from the two checkboxes. =sum(B26:B48) or something like that. But I'd like to automate it so that it just sums between the last two checkboxes in column I. I'm pretty stumped on this and I don't know how to approach it.

Here are some screenshots from my spreadsheet.