[amibroker] BarsSince Question

[steve_almond]

I was trying to calculate the number of bars since the HHV of price over the 
past 6 months (126 trading days).

This seems to work: 
A1= HHVBars(C,126);

This doesn't seem to work: 
A2=BarsSince(HHV(C,126));
It always returns zero.

Why doesn't the second expression work?

Thanks,

Steve