You only need PoE+ power if you want to use the USB port or the second Ethernet port, otherwise PoE power will be fine.
This is documented in the datasheet for the AP250 which you can find here:https://www.aerohive.com/wp-content/uploads/Aerohive_Datasheet_AP250.pdf
Clip I'm referencing:
Power Specifications
• IEEE 802.3af PoE Power: Full 3x3:3 802.11ac MU-MIMO performance, BLE and Dual 5 GHz. No USB port, no 2nd Ethernet port.
• IEEE 802.3at PoE Power: full set of features (all of the above plus USB port and 2nd Ethernet port).
