We were testing B2X balances, and found inconsistencies. Anybody please explain me this:

For our test we have used the wallet of the bitcoin genesis block "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa".

In block#0 this wallet got 50 btc block award:
https://blockchain.info/de/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f

Later, the wallet's balance increased, see:
https://blockchain.info/de/charts/balance?address=1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
and during the fork of BTG and B2X, the balance was between 66 and 67 btc.

Now, how comes that when checkint the balance, the amount is wrong:
$ bgold-cli -rpcport=10332 importaddress GSruo8yL4FswkBKWHL7mt6RLFwhxBe2GVb
$ bgold-cli -rpcport=10332 getbalance "*" 3 true
16.30927487

The same is true for B2X, for example the b2x-segwit.io api shows:
http://explorer.b2x-segwit.io/b2x-insight-api/addr/1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa/balance
"1673497591"

Can anybody explain please. Am I missing something?