using length() multi-dimensional enterprising arrays delphi

i am controlling multi-dimensional enterprising array delphi am perplexing figure out:

i have 2 seperate values initial index second index totally seperate any other.

as new values i wish grow array new value outmost presumably bound.

for new values x, y

i check:

if length(list) < (x + 1) then
   setlength(list, x + 1);
if length(list[0]) < (y + 1) then
   setlength(list, length(list), y + 1);

is repremand proceed there improved proceed grow array needed?

code1