The target is calculated over the average buying price, and the position size over the total position size (the sum of all your investments so far).
Market WAVES/BTC Current WAVES price 0.00052030 Position Size: 0.01 BTC DCA/ReBuy targets: 1. Target: -3%, Quantity: 100% 2. Target: -5%, Quantity: 100% 3. Target: -5%, Quantity: 100%
The formula is simplified because the invested amount is the same, but the original formula has it into consideration.
The original DCA strategy, count on doubling your current investment, so you should choose 100% in all your targets quantity if you want to follow it.