If you are trying to make a wallet structure out of Blockcypher, read this...

[NotATether]

If you're using the Blockcypher API, and are querying for address transactions, you need to set a really high value for the "txlimit" parameter like 10000, because certain transactions contain a boatload of input/output counts, which are cut off after a certain threshold, and this can impact the UTXO set you can calculate from the results and as a result, the balance.

That is all.