flashing

[jf254]

Hello Im helping out a friend installing a through the roof kit. (cathedral ceiling) my only question is when I look at the book they want me to only place the top of the flashing under the top shingles. I have been doing HVAC for a while now and I have always been told to start low and work the flashing up. I just wasn't sure if it calls for the installation this way for a reason. (it is a ventilated flashing) any help would be great. It is simpson dura vent

thanks Jason

 

[kksalm]

Hi.
I just punched a hole in my roof and I made many extra steps, just to be sure. I'm not familiar with your product but I would think more flashing from the bottom up would be a good thing.
Best regards....