Thanks for your analysis. My approach is more simple-minded, which is why my original post was talking about cash on hand. Can't make it much more simple than that.
You know what they say, "Keep it simple, silly". -LOL
My simple method relies on a steady or slightly increasing rate of cash added each quarter. This has been true for the last 3 quarters as follows:
Q2 2018 to Q3 2018 - cash increased by $2.7M.
Q3 2018 to Q4 2018 - cash increased by $2.6M.
Q4 2018 to Q1 2019 - cash increased by $3.6M.
(all of the above figures are based on rounded off numbers for unrestricted cash on hand)
If others don't like this method or call it "wrong", that's their prerogative. I will continue to use this model for myself, but will not post it on the board unless someone might request my valuation for PIOE.