It is obvious from your coin that they had some good die cutters in Syracuse in the 4th century. Both sides are impressive, but the Zeus portrait especially.
You give a weight of 17.45 gr(ams?) but don't mention the flan size. Judging from the picture of the coin in hand it looks like 20-23 mm. Is that the right module for a
dilitron of this period.
dilitron = 2
litrae (the half is a
hemilitron)
Since the bronze
litra was usually subdivided into 12
onkiai (corresponding to the Roman
uncia?) I would expect that the full litra was a rather sizable coin, let alone its double.
The images I have for the litra (Sear) show an impression on both sides with a large rim into which the die impression is sunk. Others show an impression on a flat surface that curves into a very thick flan. A example on
ebay came in at 28mm and 29.6 grams for a litra. So I cannot see a
dilitron weighing less.
Are you sure your coin is not a
hemilitron? If it is, then you might want to verify that $245 is a good price for a hemilitron. I know nothing of the market for any of these coins, so all I can do is ask questions.