Typically older style soffit vents on plywood are way too small to provide proper ventilation for the attic. Soooo,,, before new "open soffit" material is installed many more larger vent holes should be provided, or like we did at my home, large sections of the plywood soffit were completely removed.
Try these 2 companies to see if they are interested. I have never used them personally but they have been operating in and around Milton for a long time and they specialize in eaves, soffits, and vinyl siding.
http://mhaluminum.comhttps://www.seamlesseaves.ca