They are not 10 litre kits. It is a 20 litre kit, but with two lots of bottles to make the 20 ltr (2 sol A 2 x Sol B and 2 x Sol C).
You WILL need the starter otherwise the paper will not develop to its full potential if at all. The reason it is not included in the replenishment working solution is the paper carries over enough of the 'starter' to not need any more.
Tetenal make a 5 litre kit which does not include a 'starter', simply because it is already mixed with the other chemicals.
In my solution B bottles I tried but cannot get more than 120cc of water in an empty 'B' bottle when I fill it up to the top of the level in the unopened 'B' bottle. I have used these dilutions for over 20 yrs now and they have always proved correct.