Question about Teflon Sheet

[Ironbar 12]

I recently purchased a press from Heat Press Nation.  I also purchased a Teflon sheet to use.

First thing I noticed is that even though the unit is set for 305 deg f it is actually around 325.  I turned it back to 280 and it sits right at 305.  I'm using two non-contact thermometers to check.  Is this normal for a press to be this far off?  (Probably so for an inexpensive press)

When pressing my first shirts, I used the Teflon sheet and could not get the Sisser Easy Weed Glow-In-The-Dark to transfer.  It just stuck to the carrier paper. I was pressing for 13 seconds at 305 deg (actual temp, not what the unit was set to).

 I removed the Teflon sheet and it pressed on the first try.  Do I need to increase the heat when using the protective sheet?  Press longer?

I'm sure there is a trick here I just don't know...

Here is the Teflon "Non Stick Sheet" I am using: http://www.heatpressnation.com/pro-grade-non-stick-sheet.html

Thank you for the help in advance.  There is a wealth of information on this forum.

[Wildgoose 4,200]

Pretty common to be off. Especially on budget presses. Use an IR temp gun. Most Siser products seem to be able to tolerate a little over temperature without much problem. I have not used the glow-in-the-dark stuff to have any specific input on that product. I think I read somewhere that you should compensate a little for a teflon sheet. Like add 5 seconds or something. I switched over to parchment paper (from Walmart) like you use for baking cookies. Works better IMO and much cheaper. I found my teflon sheet ended up with wrinkles  which then show up in some vinyl. You can get a lot of press cycles on a sheet (hundreds) and then just toss it when it starts to get crisp. 

[Go-C Graphics 856]

I have found that a teflon sheet will not transfer heat as fast as not using one.   

This caused some plastisol transfers to not working correctly.   Once I stopped using the teflon they worked perfectly.