If you plan on using these radios for a school that wants something cheap and private I would strap the voice privacy and probably just use basic privacy.
I don't use the MD-380 anymore, but I had problems with the radios dropping out of EP mode if it received an unencrypted signal, or a basic privacy coded signal. The radio would then no longer function in EP mode until you rewrote it using CPS.
If in BP mode, I never had it do that.
If you use a BP key, for example- 'D8F5', it should offer reasonable privacy.
I don't see that much of a gain by using the TYT 128 bit EP mode. It uses no IV, and from what I've read the key stream is actually 49 bits.
Also keep in mind, it will process any signal it receives if on the same frequency and color code.
If it received a clear signal from some outside user and you have privacy activated on your radio, it will play garbled audio.