Not bad at all for a First Script 
However, I think you should add some fail safes here:
Simba Code:
procedure HighAlch;
begin
count := 0;
for i := 0 to Alchs do
begin
Debug;
AntiBan;
Gametab(tab_Magic);
Wait(100+ Random(100));
while GetCurrentTab = tab_Magic do
begin
Wait(150 + Random(250));
nax := Random(20)+560;
nay := Random(20)+360;
Mouse(nax, nay, 1, 1, True);
Wait(750 + Random(250));
end;
while GetCurrentTab = tab_Inv do
begin
Wait(200 + Random(200));
Mouse(nax, nay, 1, 1, True);
Wait (1000 + Random(250));
Gametab(tab_Magic);
end;
end;
end;
You shouldn't also rely/use coordinate clicking, preferably a Findcolor/Bitmap/DTM procedure is best and will help you further your knowledge of Simba and the SRL include.