If going by the spreadsheet and using he Cost per 100nm per 100kg carried as the measure of "better" gives the following:
1900D 0.20
King Air 0.12
So if going by that "yard stick", the King Air is better. Not to mention that the King Air is cheaper to purchase with a faster cruise speed. So the decision is easy right? <pushes the easy button>
But if going by the spreadsheet, we should all be flying the Lockheed Constellation at 0.03.
Everything that follows is IMO; Assuming that both planes could be filled each flight, then hands down the plane with the larger capacity apparently wins. Why? Because the operating cost are always a percentage of the revenue stream. The difference in purchase price is relatively small (about 16%) so as to come out in the wash.
But.......There's no mention of how much more of
your time is spent creating a flight load for one plane verses the other.
I just recently purchased a Pilatus PC-12 (N128CM) and in the process of flying jobs from the East coast towards the PE coverage area. Making good v$'s along the way. Per the spreadsheet, the cost of PC-12 operation is 0.07 per 100nm/100kg. So by that measure, the PC-12 is better than either of your two choices.
To me the problem with the analysis is that it does not include the value of your time. To illustrate a point, I took all of my FSE log data from Jan 1st 2015 and parsed into a spreadsheet (simple copy/paste from web page). Sorting by aircraft type, I came up with a figure of how many v$'s per hour I made in each airplane type.
>>wmburns log data from 01-01-15 through 06-03-15
Aircraft - total v$ - hrs - v$/hr
BAe Jetstream 41 Total $62,869.80 - 7.20 - $8,731.92
Beechcraft Baron 58 Total $235,822.05 - 78.53 - $3,002.83
Beechcraft King Air C90 Total $4,338.70 - 0.57 - $7,656.53
Cessna 208 Caravan Total $10,699.29 - 2.18 - $4,900.44
Pilatus PC-12 Total $67,465.03 - 13.37 - $5,047.26
Grand Total $381,194.87 - 101.85 - $3,742.71
Some interesting things emerge. The PC-12 carries twice as many PAX (10) as the the BE58 (5) and cost less to operate but why doesn't it make twice as much per hour? My theory is some of the "other" fees such as booking and ground crew fees.
Bottom line. I still stand by my original recommendation. The FIRST choice should be which plane do like to fly best. As this will be the plane that gets used more. The v$'s will work themselves out.
Then if you still can't make up your mind, then why not do an exercise like above? IE figure out which plane gives YOU the most v$'s per hour spent flying. After all, isn't your time really the most viable asset of all?