Bahamas KM# 39 weight

I just weighed my coin and it came out at exactly 5.40 gr while all sources I have found list the weight as 5.54 gr.
KM# 18 is listed on Numista and elsewhere as 5.40 gr but my coin is clearly KM# 39 (no FM mintmark and legend starts "THE COMMONWEALTH" not "COMMONWEALTH" as on KM# 18. Both numbers include a 1973 date (the date of the last KM# 18 and the only date of KM# 39). My coin is not badly worn so wear due to circulation cannot account for the weight difference. Any ideas? Could all the sources on the weight of KM# 39 be wrong? My scale has been weighing other coins just fine.

Thanks for any information.

Will

mine is 5.41 grs
dia: 22.96/23.52 mm
thick: 1.70 mm
edge: plain
orientation: medal

ole

In Krause (edition 2007) there is no weight for the KM# 18 and 5.54 g. for the KM# 39:



I have two pieces 1973 KM# 18 with weight: 5.57 g. and 5.60 g.
I also have two pieces 1973 KM# 39 with weight: 5.51 g. and 5.58 g.
So none of them around 5.40 g.
Strange, because you both have one around 5.40 g.