Adam, when cash is withdrawn from an AIM managed investment, it should be taken in equal parts from equity and cash balances. For example, a $10,000 withdrawal for RMD purposes would require selling $5,000 in equity combined with $5,000 from cash. The Portfolio Control is then reduced by the $5,000 sold from equity.
Conversely, if adding $10,000 cash to an AIM investment, $5,000 is invested in equity and $5,000 is added to cash balance. Portfolio control is increased by $5,000, the full amount of the equity portion.
For those using spreadsheets, the Portfolio Control must be manually adjusted because normally an equity sell wouldn't change it at all, and purchases would only increase it by 50% of the purchase value.
AIM manages Portfolio Control correctly for AIM-generated transactions. For externally generated transactions, it must be done with the 50/50 split between equity and cash, with Portfolio Control manually adjusted for the external transaction. This keeps AIM in the proper balance for continued operations. This method is how Lichello described it in his books.
One exception to this rule is when you have multiple investments managed by AIM. If one investment is about to run out of cash and another investment has an ample supply of cash, then cash can be temporarily moved from one investment to the other with no adjustments, and returned when cash balance rises from multiple sells. No adjustments are made other than a spreadsheet entry for each investment documenting the temporary cash transfer. I have done this in some of my early backtesting with no issues, unless the supplying investment itself runs out of cash before it is returned.
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