Videos are gettign skewed upon exporting custom export size

Hi. I am new to After Effects and I apologize in advance if this is a silly question. I have created a video in AE that will live on a custom monitor with target dimensions of 768px height by 1360px width. I have set the composition settings to these dimensions. In my render queue I have it set to export at these dimensions as well. I have experimented with locking the aspect ratio on both the output module and have experimented with the stretch option to try to force the video to export at the desired dimensions.

The video export file's info window says it is 768x1360, but when I view it in Quicktime and Itunes, the video is actually beign resized to 699x1360. When I open it in Adobe Media Encoder, it sees the file dimensions as 699x1360. The video looks slightly skewed and unacceptable.

Can anyone give me any pointers to force AE to export this video at my desired custom width and height?

Width: 768px
Height: 1360px

I'm not sure what some of the following mean, so not sure how I should set them, so any suggestions are welcome. but currently they are set
Pixel Aspect Ratio: D1/DV NTSC (0.91)
Frame Aspect Ratio: 1280:2497 (.51)
Frame Rate: frames per second
Resolution: Third (256 x 454, 454 KB per 8bpc frame

The specs from client are as follows:
Resolution: 768x1360 (wxh)
File Type: .mov
Codec: .h264
Aspect Ratio: 16:9