Cheap POE+ 802.3at Injectors

I'm looking for some cheap POE Plus 802.3at (NOTE that is IEEE 802.3at not IEEE 802.3af inejctors) It's for some Cisco Aironet 1250 APs. They have both the 2.4ghz and 5ghz radio modules install and both are mimo. I can power them with standard poe however they run at reduced functionality and don't provide mimo either with the standard 15w. There is a Cisco braned one but even used from a reputable source they are pretty darn expensive. It's for a non profit and there are three of them. I'm wondering if I should just scrap them and get some different APs.

I'm wondering if part of the price difference isn't because there is likely some chip that is used to tell the device I'm POE+ not just POE as the APs will tell you it's not an approved POE source so functionality is reduced. Even with the 802.3af injectors that are a little over 24 watts I have produce the same result. 802.3at is 25watts so 24 watts on a short patch cable is well within the limits of drop over a run of cable that would be within tolerance. anyone happen to know if these use an identification chip unlike 802.3af?

All of these will be on different access switches as they are in different areas of the location. So small POE+ switch won't work it must be individual injectors.

And also reviews like on this one make me think there is a POE+ Identifier chip rather than just being based on the source wattage. http://www.amazon.com/BV-Tech-POE-I100G-Gigabit-Single-Injector/dp/B00B4H00EO/

Ended up finding this

Enhanced PoE use Cisco Discovery Protocol to auto-negotiate a power level in excess of 15.4W per port.
The Cisco Enhanced PoE switch informs the powered device (PD) of the power level it is capable of providing, and the powered device then selects the appropriate power level.

http://www.cisco.com/c/en/us/products/switches/epoe.html

So it may even need to by a Cisco Branded device... Ugh. Cisco!!! Why???