Cumulative cost by week
Knock (1.25% + prime+1%)
Zoom Casa carry (0.5%/wk after 21 days)
Homeward rent + 7% cap
Reading the chart.
All three programs start cheap. Knock's interest compounds monthly — the slope steepens after day 30. Zoom Casa starts flat (the first 21 days are free) then adds 0.5% of advance per week. Homeward's rent is flat but caps the total program cost at 7% of home value, which makes it the best choice on very long holds.
The break-even.
For most markets with DOM under 45 days, Knock wins. Between 45 and 75 days, Zoom Casa overtakes. Past 75 days, Homeward's ceiling wins. Run this against your own local DOM.