The reason the gap is so large is because it recalculates daily, estimating that you keep the same pace of honor farm all week and doesn’t include others INCREASING their honor farmed.
Basically what you want to do is aim for a bracket above or at your current rank. (better than your current rank)
just earn like 200k honor per week, then at rank 8 u earn like 300k then for the last what like 3 weeks? from r9 + earn like 400k roughly
Of course this all depends on brackets. The amount of honor you farm is about what BRACKET you get placed in that week and the BRACKET determines what rank you get that week.
If you are 3 brackets above your current rank on tuesday you SHOULD jump an entire rank. Likewise if you are say a knight (rank 6) and you are in sergeant bracket (br 3 or 12 depending on how u view the brackets order) then you will lose rank but I believe your decay is capped at 20% per week? etc