I have issues with the use of extra load slots, i have them set to 30 slots and when the mission is loaded and VAS is accessed, only 10 slots are available, I've had this issue for a while. This is what my config looks like.
vas_onRespawn = true;
vas_preload = true;
vas_disableLoadSave = false;
vas_customslots = 29; //9 is actually 10 slots, starts from 0 to whatever you set, so always remember when setting a number to minus by 1, i.e 12 will be 11.
vas_disableSafetyCheck = false;