Weight of coin does not match with Numista

I recently brought a 1973 British Virgin Island proof set. When I opened the proof set and weighed the 1 Dollar (.925 Silver) coin. It is around 1 gram less that what is posted in Numista (https://en.numista.com/catalogue/pieces15537.html). Also I took the 50 cents proof (Copper-nickel) and it's weight does not match either.
I have tested my weighing machine with some known coins and the weight is showing up perfectly. So I know that the machine is working correctly.
Has anyone else saw this kind of issue (with this one or any other coins)? The coins look perfectly original to me and their diameters are exactly matching. One can try to mimic a silver coin with fake but why would someone want to mimic a copper nickel coin (it's not rare either).

Don't worry, your coins are OK, the Numista data are not correct, I found this error many times for Albanian coins, especially aluminum ones.

What you can do is try to modify yourself in the coin sheet and wait until somebody from the Team approves it.

Thanks, I thought so. The coins look legitimate from all angles. What is surprising is that the NGC website mentions the same weight as Numista.
If anyone has a British Virgin Islands 1 Dollar Proof from 1973-1984, maybe I can double check.
Anyone?  

The weight is also the same in the standard catalogue of world coins, but in 1985 the silver dollar weight is 24.74g so possibly produced at a later date. To be honest without looking into I'm not sure why this is. If I have time I will have a better look into this.

Verweis : tony_k_1965The weight is also the same in the standard catalogue of world coins, but in 1985 the silver dollar weight is 24.74g so possibly produced at a later date. To be honest without looking into I'm not sure why this is. If I have time I will have a better look into this.

That will be great.

I have a good search through various sites and forums but can't find anything that mentions about the weight being different. sorry

Verweis : tony_k_1965I have a good search through various sites and forums but can't find anything that mentions about the weight being different. sorry

 Anyways... They are beautiful coin in any case. Thanks

Verweis : sujit_kumar

Verweis : tony_k_1965I have a good search through various sites and forums but can't find anything that mentions about the weight being different. sorry

 Anyways... They are beautiful coin in any case. Thanks

Out of curiosity, I brought another 50 cent Jamaican proof coin of same 1973. The weight exactly matches with my previous one. So I guess more chances that the Numista details are not accurate.