Known bugs:

(gh1,gh2*) Early whammy that interrupts a sustain note of a different colour will lose ticks; this is not catered for in the code.
(gh1) Caveman Rejoice hard and expert charts no-squeeze scores are higher than big squeeze scores.
(gh1) Thunder Kiss 2nd activation appears impossible on big squeeze + charts.
(gh3:a) All The Young Dudes charts picture are truncated, however path and estimates appear fine (thanks LemonMeringue)
(gh3*) ps2 version has a calculation error (in the game itself) that results in less ticks on sustains than other versions.
(gh3*) sustain notes finish 1/8th of a beat earlier in the actual game than in the charts.
(gh3*) sustain notes have a points burst at the end which can be manipulated for more ticks under SP in certain circumstances.
(gh3:a) DrSham reported that Back In The Saddle easy 6th SP phrase, isn't.

Planned features:

(gh3*) blank charts for other game types (co-op, battle mode).
(gh3*) blank charts for boss battles.
(*) redesign the webpage; remove dependance on ScoreHero images; make it easier ot navigate and update.
(*) display the general parameters used to generate the charts for the more technical people.
(*) (maybe) link the charts into the stathero database to centralise the information.
(*) automatically pull the top scores and update the index pages each day.