Import Frames to Layers Way Off Range

Very simple issue here. I am hoping someone knows the workaround. I have a 3 hour movie that I need to grab a series of stillshots from. The scene I want is possibly 50 frames long and I just want this one particular frame.

I use the Import Video Frames to Layers command and drag the start marker to the beginning of my scene according to what is on the video preview. Then, seeking by frame by frame I finally get to the end of my scene and set the end marker. When I say import, it gets an entirely different set of frames, though the imported number of frames seems about right. Granted the controls are so completely ridiculous and unusable as an interface for video, but you deal with this as best you can. I have even selected 500 frames ensuring my start and end markers completely covered the scene I want. Still, it's off by a lot. Every time.

Surely someone else has had this problem and can recommend a solution. Maybe I should try NOT selecting my scene in the hopes that Photoshop can be tricked by reverse psychology? The video is too big to import the entire thing and I literally need ONE FRAME in the highest possible resolution. 

Any suggestions? I'm using PhotoShop CC2019 since Adobe ruined all of the plugin compatibility after 2019 and I haven't spent hundreds of dollars for updates. I'm stuck using 2019 for now.  Thanks in advance for your help.