I've been 'playing' with my cards - 'manually' ...
I've found:
Coles is better than Woolworths ( Coles self-service check-outs have a faster system, and with less options to press )
You can continue onto your second '50' transactions on a Coles machine ( if you are using a second card ), and continue to split the same tranasaction. However, today, I 'crashed' a machine at 99 transactions. Thus, I would recommended, that you only do 50 at a time, and use each card for a separate 50 tranastctions.
Keeping in mind also, that if you have 'other' uses for your BW card, such as having any Direct Debits taken out, that reduces your 50 transactions per day.
I've found, that once a Coles or Woolworths machine 'crashes', it causes a 'scene' - the attendant starts asking questions; other people stop and stare, and it slows the whole process down.
My advice is now - don't go for '50' .... settle for 48 or 49 on each card.
Taking it to the '50' increases the risk of the machine crashing.
I also noted today, the 'rounding' process for Coles ...
I bought milk @ $3.00
Two cards. 50 transactions each card, @$0.03 each transaction. At $2.97, the machine 'rounded' it off, and I got the last $0.03 for FREE.
Gee, I was happy with myself today !! ( lol )