How is taxation affecting your buy/sell decisions?

For simplicity, let's assume a high bracket of 50% for taxation, and that you bought:
10 BTC @ $10
10 BTC @ $100

If BTC were to hit $1000, and you sold 10BTC (half your holdings), and you cashed out $10,000 (for a net gain of $9500)...

And then, BTC falls to $500, and you buy $10,000 back in (+20BTC).

You've now got 30BTC, but a tax liability somewhere around $9500 of gains, or $4750.

You would have had the same net effect by buying $4750 worth of BTC when it was at $475 each.


Am I just false in my claims above? It seems like trying to play the bounce, you're more likely to lose out due to tax and it's just better to sit on unrealized gains. I must be missing a key point.