Each bar i'm using is 30 mins, so I'm trying the following code:

//////-------------MA LINE CROSS CHECK (crossNOW, crossTF)
bool MAcrossOver = MAshort[1] < MAlong[1] and MAshort[0] > MAlong[0];
bool MAcrossUnder = MAshort[1] > MAlong[1] and MAshort[0] < MAlong[0];
bool MAcrossNOW = MAcrossOver or MAcrossUnder;
if (MAcrossNOW){
timer();
}
var nback = 3;
bool MAcrossNOWrecent = timer() < (nback*1800000);

I'm hoping "MAcrossNOWrecent" will tell me if the event (crossing of two MA lines) occurred less than 3 bars ago (1800000 milliseconds *3).