I have direct knowledge of a red light HTA 144/18 that was reduced to disobeying lane light HTA 144/10 ($85.00+$30.00 and no points). It seems a lot depends on your driving record. The better it is the better deal you get. If someone is receiving tickets on a regular basis the province tends to look at them like they're a "cash cow".
The prosecutor is usually available to discuss a deal anytime before the trial. Check at the office you'd pay the ticket at (the POA office) and they'll you his/her hours of availability. From what I've heard most of the prosecutors are fair. Definitely visit them before the trial date, so you have time to think it through.
These are just my opinions and thoughts.
Again, good luck.