how to drill 下る without losing 0.4% efficiency

I hit phase 4 of my 25k deck and 下る is killing my stats. My current SRS interval is 3.5 days but I keep failing it, dropping my daily retention to 89.2%. To fix this, I set up a 3-step micro-drill: step one is a 10-rep active recall block at exactly 08:00, step two is pairing it with 固定 for semantic anchoring, step three is a 120-second speed-run. No room for boredom when you gamify the spreadsheets.