It's the percentage decrease which is important, not the amount. Most of us wouldn't say "only reduced by 5mg" even when the dose was larger. When I was at 25mg, the rheumatologist had me dropping 2.5mg per week, with a drastic readjustment at 10mg (1mg every 2-4 weeks). Really, is your doctor okay with your dropping from 10mg to 5mg?