I seem to remember reading that there is a big price jump for any knife over 6.5 sun (~200m) because he doesn't make that many of those. Murray works in batches, making a bunch of similar knives all at once. The smaller ones he can make a large batch of and sell the extras easily on his website. The larger knives are more by request only, so they have a higher premium. So the price difference between a 195mm knife and a 210mm one will seem huge, but the gap between a 210 and a 240 won't be so bad.
"God sends meat and the devil sends cooks." - Thomas Deloney
Ohhh, always gotta read the fine print!