Having read the several threads here about supply and unit/element replacements and reinforcements, I realize that the details of that have really gone right over my head during play - it's a part of the game I have ignored, no doubt to my side's detriment.
So I wondered: how hard would it be for you guys to add a bit more detail to the unit/stack info when the cursor is over it: a short line something like, 'using x suppy chits, drawing from x province,' or 'replacing at the rate of ...'? Whatever is appropriate.
I find the information provided by the tooltip very useful. However the information is useful when considering the ability of your units to operate without a supply source rather than resupplying at a supply source.
Basically the game has two different supply situations. One is use of supply when operating in the field and a second situation is maintenance/resupply when located at a supply source. The tooltip provides useful information on consumption of supply during operations when resupply is unavailable or very limited but it does not provide useful information for resupply.
When you use your tooltip to examine a formation's supply information, you will find the total supply points contained by the formation as well as the monthly supply use of the formation.
Example: You have 4 fully supplied militia regiments and a supply wagon. Each of the militia regiments have 16 supply points for a total of 64 supply points for the 4 militia regiments and the supply wagon has 64 supply points. Thus the total supply point stock for the formation is 128 supply points. This is the first number provided by your tooltip over the supply icon.
The second number is your monthly supply consumption. Each militia regiment uses 8 supply points per month for a total of 32 supply points consumed by the 4 regiments. The supply wagon uses 4 points per month. Thus the total monthly consumption by the formation is 36 supply points. This is your second number representing formation monthly supply consumption. (Note that your units consume precise numbers of supply points unlike supply sources which provide exact supply chits. This is where the wastage concept comes into play.)
By comparing the two numbers, 128 total supply points and monthly consumption of 36 supply points, you now know that your formation can survive approximately 3.5 months in the field or beseiged before starvation becomes a major duty problem. If the formation did not contain a supply wagon, then the total supply would be 64 supply points with a useage of 34 points per month. Then the unit would only survive 2 months without supply which is typical for most regular units. (It is also very useful to know that most beseiged cities/forts will only last 2-3 months before losses begin due to starvation if they lack supply wagons.)
Information on survival time without resupply is very important when planning operations. How long can I maintain a siege of a fort before running low on supplies? How long can my formation survive a seige before relief must arrive? Or can my formation go cross country through the barren west to reach Fort Niagra...and return if the assault fails, without starvation? I have discovered the hard way that units will die when out of supply.
I find the tooltip gives very useful information for operations but really is not applicable to resupply or locating an appropriate region which will meet the monthly supply needs of a formation.
A second number which provides the supply levels, not points, needed from a supply source to 100 percent maintain/resupply a formation's supply requirements would give a complete picture of the two important supply considerations of a formation.
For example: The 4 militia units and 1 supply unit might have the following information. "Your current stock is 128 supply points, your useage is 36 supply points per month. This formation requires a 9 supply level source to maintain 100 percent supply."
Perhaps something for the future "to do" list? It is not really hard to calculate ourselves but it would be more convenient to simply use the tooltip and might help those of us mathematically or time challenged.