From Thursday 07/01/2021, the basic income on BILLEXC is calculated not by the token denomination, but by the amount of actually converted CENTUSX.
a) you have converted 160 CENTUSX to 100 BILLEXC: You receive the basic income on 160 CENTUSX, not 100 BILLEXC
b) you have converted 40 CENTUSX to 100 BILLEX: You receive a basic income on 40 CENTUSX, not 100 BILLEXC
For BILLEXC purchased on Stellar DEX (exchange), basic income is accrued based on the rate of 33.33%, that is, the auction clearing price.
You bought 100 BILLEXC on Stellar DEX (exchange) at a price from 1 to 100%: You receive a basic income on the amount of 33.33 BILLEXC.
Thus, everyone will be fairly accrued the same percentage on the actually converted CENTUSX amount, and the size of your discount for the auction or additionally accrued BILLEXC is your main income.
Please be reminded that the basic income rate is floating and can change both upward and downward depending on the algorithmic supply of CENTUSX.
The basic income is accrued in BINCOME tokens on Mondays and Thursdays.
Best wishes, CENTUS