Broad-rock, yes, you are correct for normal impulse waves in that wave 4 should not penetrate wave 1 territory. This can only be permitted in the event of a leading diagonal (of which the waves 1 and 4 mentioned would be subwaves). This is not yet out of the question, but I fell it's now unlikely and that it's more likely that my wave count is wrong and 80.675 was probably the top of wave 5.
For now, I've closed my long on this pair based on this chart with a revised wave count:
dl.dropbox.com/u/20815047/USDJPYdaily13_11_12.gif
So, it looks like the trendline bounce may be a wave B with wave C down to somewhere near the 61.8% Fib to come. Supporting this idea is the breakdown and backtest of the RSI uptrend which is when and why I closed my long. In addition, as Broad-rock points out, the low at the trendline was below the wave 1 high so there's a number of factors coming together to support the breakdown of the previous wave count.
This just shows that you can never completely rely on a wave count and that we should always be on the lookout for alternatives and/or contrary analyses. In fact, whenever I take a position, rather than look for more analysis to support it, I prefer to look for analyses against it. If I can't find any then I ought to be OK. It's easy to lose objectivity if you're looking to support your own view...
ATB