Wait a sec, is that DDD.MMM or DDD.DDD? If the part after the decimal is minutes, i.e. only goes up to .599, I could see that causing problems, especially if you have helo guys from out of the area or otherwise unfamiliar with your system.

Most GPS have a display option of DD.DDD (decimal degrees, not minutes) which will actually give more precision with the sme amount of digits.

Just a thought from someone who uses GPSs but knows next to nothing about flight ops or fire/rescue.