Autolevel with BL Touch only scans single row

Seasons' Greetings: I recently installed the latest version of Marlin on my CR10S 5 a couple of weeks ago. This was after installing a BL Touch sensor. I configured the example configuration for bi-linear auto bed leveling, at least attempted to do this, mostly by uncommenting '#define BLTOUCH,' '#define AUTO_BED_LEVELING_BILINEAR,' ;#define RESTORE_LEVELING_AFTER_G28,' '. I set the GRID_MAX_POINTS_X (line 1340) to 4. The other features of the firmware upload are working very well (thanks to the help of a couple individuals on this forum). I was wondering where in the configuration file is the 'GRID_MAX_POINTS_X' value assigned to the Y- direction? I would any insights and assistance anyone could share. Thanks for your help.

GRID_MAX_POINTS_Y is typically defined to same value as GRID_MAX_POINTS_X in file configuration.h

Quote

#define GRID_MAX_POINTS_X 3
#define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

[marlinfw.org]

That is what a couple of YouTube videos that I watched on setting up the BL Touch in Marlin had indicated. I guess my question is: why didn't the GRID_MAX_POINTS_X 4 define the GRID_MAX_POINTS_Y?

Quote
DragonFire
GRID_MAX_POINTS_Y is typically defined to same value as GRID_MAX_POINTS_X in file configuration.h

Quote

#define GRID_MAX_POINTS_X 3
#define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X

[marlinfw.org]

It will be alright when I define

#define GRID_MAX_POINTS_X 3
#define GRID_MAX_POINTS_Y 4

I would like to increase number of probing points without loosing centre point (25 points take to long time).

There is some setting in configuration.h to allow change those parameters on printer screen?

Most likely you have PROBING_MARGIN set to the default of 10 - this means it can't probe any of the rows/columns that are closest to the edges. PROBING_MARGIN is designed to handle probes that are inaccurate near the edge of the bed (inductive/capacitive) and can be set to 0 for a BLTouch.