Explanation of sequence
You are correct, when starting a sequence (1st hand or after a loss), start at 2 units. If you win, go to 1 unit; otherwise stay at 2 units. (The key is the initial bet is larger than the 2nd bet)
Once you win, your sequence of bets is 1-2-3-4-5.... on up until you lose. You can pause at a level, say 2-1-2-3-3-4-5, etc. When I have used it, I usually stop at 3 on negative decks, and go up to 8 as you continue to win. If the count jumps up, and I have won a double down/split hand, I will go up much quicker than the "normal" single unit increment. I have a stack of chips in my betting circle and I put them to use.
How does it work on choppy tables? My definition of a choppy table is that you rarely win more than 1 hand in a row. You are winning some hands, however, as otherwise I would bail.
By definition you will win the 2 unit bet, and may lose the 1 unit bet ...of course things can go good or bad depending on when doubles and splits occur, but that can really never be predicted regardless of the betting strategy. If I choose to use the progression, I bail after 4 straight losses.
Again, if I am losing my doubles and splits, and not making up for it with the single unit bets, I will bail; it's not working for me, regardless of the count. I'm sure I'll catch flack for not continuing to bet as the count dictates, when I have "the advantage" lol. The progression isn't for every table on every hand. It may come into play and may not.