If I have 100 units at a cost of 1 dollar and a current value of 1.25 dollars, I currently have a 25% profit. If that current value begins to drop I would like to begin selling off units over a price range that represents a 40% decline in PROFIT so in the above scenario I will be completely sold out if the price drops to $1.15
In the above scenario the distribution is pretty simple in that it can be assumed that I was able to sell the exact number of units at every increment needed. Where I run into an issue is when conditions aren't as favorable. Lets say I wasn't able to sell exactly 10 units at every penny of decline, and I possibly even missed whole increments. In such a scenario lets say I was able to sell at the desired rate until I reached 1.19 where I was only able to sell 6 of the 10 units I expected... and then the price gapped to 1.17 .
How would I go about factoring in actual realized quantities & sale prices and adjust my selling distribution to maintain my ideal average exit price of 80% of maximum profit? So that at any given increment I would be able to determine the exact number of adjusted units needed to be sold to maintain the desired distribution.
Following your scenario, you start with 25 profit and want to sell 10 units at every penny drop. Selling $10$ each at each point from $1.24$ to $1.15$ nets you an average price of $1.205$ and a profit of $20.50$ This is a little less than a $20\%$ reduction in profit-it is only the last $10$ that had a reduction of $40\%$
If you want to maintain the total revenue of $120.50$ and miss some chances, you need to "bring up" some that would have sold for less. So now at $1.17$ you need to sell the $14$ you wanted to sell above that, the $10$ you want to sell at $1.17$ and enough to make up the $0.18$ profit you missed by being late to sell the $14$. That would be to sell one more item (and be a penny short) or two more items (and be $16$ over).