Hi MCDHU,
Didnīt remember this thread.
Agree on everything.
N1 can definitely be lower than 80% on the A319īs with FLX. This will only occur at very high Flex temps though. Associated performance margins (spread between OAT and Tflex) will be such that beta-target and (conventional) sideslip indication both suffice for flying the a/c inside the envelope. So I would not select TOGA for the sole purpose of getting the blue target back!