I setup the following Forecast Settings:
Days to Forecast: 150
Days of Accounts Cycle: 15
Day of Month to start Forecast: 0

Then looking into the Advanced tab I see MinBal/MinDate (Min column) pairs of columns followed by MaxBal/ManDate (Max column) pairs of columns.

Here I expect to see 10 Min column pairs followed by 10 Max column pairs.

Instead I see 9 Min column pairs followed by 9 Max column pairs; HOWEVER the underlying data is clearly for 10 pairs. This is understood for the following reasons:
1) The balance and date in the 1st Max column pair contains the values belonging to the 10th Min column pair.
2) The Max column data ends too soon (2 data points are missing, one because there are only 9 columns and one because the 1st column is, by error, populated my the last Min column's data).
3) The Max column data is off-by-1 relative to its column labels, e.g, the 2nd Max column has data for the 1st Max column, the 3rd Max column has data for the 2nd Max column, ...

Reproducible: Always

Steps to Reproduce:
1. Setup the aforementioned Forecast Settings.
2. Hit Forecast.
3. Check the Advanced tab.
4. Observe data to be incorrect as described in the above details.

Actual Results:  
18 column pairs of data + 1 average column
10 column pairs of data from Min data set
8 column pairs of data from Max data set
9 column pairs labeled "Min"
9 column pairs labeled "Max"
data in 10th column pair is from wrong data set
data in columns 11-18 are off-by-1 because the 10th is occupied by data from the previous set

Expected Results:  
20 column pairs of data + 1 average column
10 column pairs from Min data set
10 column pairs from Max data set
10 column pairs labeled "Min"
10 column pairs labeled "Max"
All columns appropriately mapped to data