IsPressed works for one key, but does not for a key combination?

Hello,

Background
1) AutoIt : 3.3.8.1
2) OS : Windows XP SP3

Issue

I am attempting to create a set of keyboard shortcuts, as shown in the code below:

#include <misc.au3>

Local $hDLL = DllOpen("user32.dll")

while 1
HotKeySet ("a" , "_keyA")
wend

Func _keyA ()

; DOES work
; Wake + Left = Left
If _ispressed ("FF") Then
Send("{LEFT}")
Endif

; DOES NOT work
; Alt + Wake + a = Home
; If _ispressed ("FF") and _ispressed ("12") Then
; Send("{HOME}")
; Endif

EndFunc
DllClose($hDLL)

One of them, as indicated in the comment, works and sends a Left when pressing "Wake + a". The other one when sending "Alt + Wake + a" does not work. Could someone please let me know what is that I am doing wrong?

Thank you for your time.