Pre-recorded EP tape keeps playing at SP

[AdamAnt316]

Hello everyone. Some time back, I picked up a VHS copy of the cult classic "UHF" at a flea market. I'm guessing it was made not too long before Orion went under, as it states right on the label that it was recorded in "EP MODE", and has the lesser amount of tape in the shell to match.

I tried to play it in our Samsung TV/VCR, which I'm guessing uses a Funai mechanism. When I start playing the tape, the 'SP' designation appears on the screen, and the tape plays way too fast. With the tape stopped, I can use the SPEED button on the remote to select between SP and SLP, but when I press play, it automatically switches to SP every time. I tried covering the record notch on the front in case it was making an assumption (it already starts play automatically when a tape with the notch removed is inserted), but no dice. I also tried another pre-recorded tape recorded in EP speed (another cult classic, "Plan Nine From Outer Space"), and playback started at the proper speed. I tried the tape which prompted this query in a different VCR, and it played at the proper speed.

How does a VCR determine a tape's intended speed? Is it a notch in the shell as with audio cassettes, or a signal on the tape itself? Is there a way to trick the VCR into starting playback at a certain speed? Inquiring minds like mine want to know..........
-Adam