vivoactive has 64 colours but only 16 defined in the SDK.
What are the other colours?
Here's a spreadsheet another developer wrote a couple years back that shows the 16 and 64 colors, along with the hex values:
https://docs.google.com/spreadsheets/d/1moYO2F3ltqbEde_vHaoKstnXLRR4AgQgQ4Yp_aGQPn4/edit#gid=0