Placing guides before/after the video?

[Zueuk]

There is a strange discrepancy between LTXVAddLatentGuide

Latent index to start the conditioning at. Can be negative to indicate that the conditioning is on the frames before the latent.

and LTXVAddGuideAdvanced

Frame index to start the conditioning at. (...) Negative values are counted from the end of the video.

Besides, if we can place latent guides before the video, why LTXVExtendSampler reserves extra latents for overlap, which apparently results in longer generation

The total number of frames generated is frame_overlap + num_new_frames, and then the new video and the previous video are fused

Can we really place (latent) guides before/after the empty video latent to "inpaint" the footage in between?