Here is how the various screens of the game are placed relative to each other, based on the engine's (NES MAKER) way of handling them.

The top left-hand corner screen coordinates are considered as X=0 Y=0 (with X standing for columns and Y standing for rows), and the bottom, right-hand corner screen is at X=15 Y=15. The map seems to loop on itself, with the OOB manipulation coming from X1Y0 to X0Y0 sending to X15Y15 instead.

It looks like coming to the end of a column (e.g.: X15Y0) and continuing to the right makes you progress 1 line (making you end up on screen X0Y1), but columns lap over themselves (going down from X14Y15 will send you to X14Y0).

Also, there are only 7 columns for the row containing the title/ending screens. This is going into assumption territory after a bit of empiric testing, but it looks like that rather than the actual relative position on the grid, the system is kinda trying to use your coordinates to decide which screen to send you to. For example, going down from X4Y5 would probably send you to X4Y6, which makes sense numerically, but on the grid, it instead looks like it should send you to X2Y6.

I'll let figure out how to optimize all that though ;)