Budd,
First the relevant rule:
46.51 (Squad Leader)
● ART fire during the DFPh affects not only those units in the Blast Area at the time of fire, but all units which moved through the Blast Area during the immediately preceding MPh.
●Such units are “brought back” to the first hex of the Blast Area that they entered in the preceding MPh.
● If the moving unit survives it may retrace its previous movement to the hex it occupied prior to the DFPh.
● However, if that movement takes it through another hex of the Blast Area it would undergo artillery fire again in that hex.
Referencing the second sentence, the key word "entered" precludes the hex of origin as an FFE candidate even if the originating hex is within the blast area.