I've tried both KVCD compatibility tests on an Apex AD-1500 and here are the results:

compat.test#1
----------------
KVCD 352x240 = OK
KVCD 352x240 plus = OK
KVCD 352x240 LBR = OK
KVCD 352x480 = audio drops (video OK)
KVCD 352x480 plus = audio drops (video OK)
KVCDx2 1CD (704x480) = audio drops (video OK)
KVCDx2 2CD (704x480) = audio drops (video OK)
KVCDx2 plus (704x480) = audio drops (video OK)
KVCDx3 (528x480) = video scrambled & audio drops
KVCDx3 mod (544x480) = jerky video & audio drops

compat.test#2
----------------
KVCD ULBR = OK
KVCD LBR = OK
KVCD 352x240 plus = OK
KVCD 352x480 plus = jerky video & audio drops
KVCD 704x480 plus = jerky video & audio drops
KVCDx3 528x480 = video scrambled & audio drops

From the compatibility page:
Apex AD-1500 - 352x240( 288 ), KVCDx3 - Also at 480x480 but re-mux as SVCD and burn as SVCD.

-kwag