If I want to calculate the difference between today's low and yesterday's low, I can use this formula:

If(LOW < Ref(LOW, -1),  LOW - Ref(LOW, -1), 0)

However, I want to find the total sum of all the differences for the WEEK, but ONLY when today's price is less than yesterday. For example,

Fri =   1.08   

Mon = 1.00   (8  cents lower than Friday)

Tue = 0.90   (10 cents lower than yesterday)

Wed = 0.85   (5 cents lower than yesterday)

Thu = 1.20    (don't include it, because it's higher than yesterday)

Fri   = 1.00   (20 cents lower than yesterday)

The sum of ONLY the ones whose price is lower than the day before = $0.43.

I guess another way of interpreting this is:

If Fri low < Mon low, and Tue low< Mon low, and Wed low< Tue low, and Thu low< Wed low, and Fri low< Thu low

then

Sum up (Mon low - Fri low) + (Tue low - Mon low) + (Wed low - Tue low) + (Thu low - Wed low) + (Fri low - Thu low)

I was looking the different Functions, but I cannot seem to figure it out.

Edited by user Tuesday, November 17, 2015 3:52:47 AM(UTC)  | Reason: Not specified