Using rigid foam board as a soffit chute?

[StatGSR]

Over this summer i will be fully insulating my garage. I am currently ripping down the rigid foam board that is attached to my ceiling to make way for sheathing and blow in insulation. I also have no other practical use for the foam board after i get it all down. I know i need to maintain ventilation to my soffit vents when i put in the blow in insulations so i was wondering if there is any reason why i shouldn't use my scrap foam board to make soffit chutes. My plan would be to cut it to match the width between trusses and wedge it into place (obviously leaving an air gap between the roof and the foam). I know it may only save me like $50 from going out and buying "the real deal" but besides that any objections/thoughts?

for reference, here is the current state of my garage ceiling, you can see the existing foam board i am taking down as well my exposed trusses

 

[Zick]

Don't see why not, you just need the air gap and those store bought soffit chutes are either foam or plastic anyways.

 

[Steevo]

Although re-using what you have is the most "green" solution, I found that the store-bought rafter-vent stuff was the fastest and easiest to go with. Using the kind linked below also allows the insulation to reach out over the top of the wall, eliminating a cold spot.
http://www.lowes.com/webapp/wcs/sto...3-1/2" x 36" Rafter Vent with Baffle UDBV2346