Bahamut's Zaghnal performance post-patch...

[Stromgarde]

As closer you approach 100%, each % of haste means more. I don't have the exact formula handy, but it is indeed an accelerating return.

[Nagamaki]

You need to compare the leftover, which is the actual delay your weapon ends up at.

8% of total delay is 11.1..% faster than 9% of total delay.

[Keno]

Is it something along the lines of: 480 base delay, 91% reduction = 43.2 delay, 92% reduction = 38.4 delay. Percentage difference in delays is therefore not 1% but 11.1% difference?

EDIT: Just read Nakagami's post, understand now. Thanks.