Not quite mate, the tax bracket the individual is in should not really impact the decision to hold or sell.
Also, the calculations you are doing are incorrect.
Holding for more than 12 months is always better if the gains are significantly better than those of an earlier exit. But, the share market can be unpredictable, however, long-term, smart investments are generally where handsome returns are made.
Calculations need to be made on a case by case basis for CGT events and is a commonly misunderstood area of tax. See your tax agent for advice before selling an asset at any time.
