Good article, worth the read.
https://warontherocks.com/2016/08/oa-x-more-than-just-light-attack/
From the article and his math seems reasonable:
These platforms can consolidate the current CAS eco-system, which is tried and true, but extremely tired and growingly geriatric. A pair of F-15Es or F-16s performing air support is supported by a KC-10, receives intelligence or targeting information from an ISR asset (i.e. MQ-1/9, MC-12, or U-28), and controlled by a Joint Terminal Air Controller (JTAC). This construct is simply inefficient and expensive. What’s more it only exists as a result of continually adapting conventional assets instead of investing in an enduring solution. Adaption in the beginning of the conflict with current resources is tolerable a stop-gap, but 16 years later, this expensive stop-gap formula remains.
The total cost to operate a single CAS orbit as described above is astonishing: over $64,000 per hour or $1,000 per minute per combat air patrol.* The F-35 will only increase the bottom line, as it actually brings less, not more, capability to the type of air support used the past 15 years — and it will cost exponentially more to operate than the aircraft it is replacing. The F-35 will not have the following for several years (or longer): the small diameter bomb, IR marker, video down-link, and EO/IR sensor fidelity that equals currently deployed fighters. Accepting the published $42,200 cost per flying hour, a formation of two F-35s will grow this price-point by 68 percent, to $107,800 per hour. By comparison, OA-X is projected to operate for under $4,000 per hour, including personnel costs — a 96 percent reduction in operating cost to support a generational war against violent extremism.
If the now-operational F-35A deployed to the Middle East and flew a typical 8-hour Operation Inherent Resolve (OIR) sortie, it would cost nearly $800,000 per mission as described, not including ordnance expenditures. For every 20 forecasted OIR F-35 missions flown, the Air Force could buy an OA-X platform (assuming $15 million for either the A-29 or AT-6). As another comparison, suspending a single day of current OIR operations ($11.9 million/day) would almost buy an OA-X platform.
Not to use hyperbole but I'll just use hyperbole, this decision not the aircraft itself, but the decision to buy or not, an appropriately capable and cost effective solution to this mission may represent an almost existential moment for the AF.
Can the institution act when confronted with a shift in the operational environment to a new form, outlook, paradigm, etc... when that is contrary to the direction that the institution has been traveling for the past 35+ years? Can it act in a way on what it needs to do rather than what it wants to do?