The longer your chain, the more fees you have to pay for your child transaction.
exactly as he said. just think of the whole chain as one big transaction.
add up their tx sizes and calculate the total required fee based minimum fee minus already paid fee
lets say: txA 500 bytes fee 5000 sats (10s/B) , txB 500 bytes fee 10000 sats (20s/B) output from txA used as input in txB,
so you want to do CPFP using output from txB as input in txC, with your txC 250 bytes
assuming current minimum fee is 300s/B then the fee would be:
( (500+500+250 B) * 300 ) - 15000 = 360000 sats (0.0036
BTC)
please cmiiw...