If you follow the trends of the network, a 45-50% jump in hashrate and difficulty was to be expected, but if the size of the network grows
I've been mining with my new Jupiter for a week now. Performance has been fluctuating 480-550 Gh/s over the past week, with daily take varying 0.81-1.1 BTC per 24h (average 1.0 per day) -- depending on performance, pool luck (BTC guild) etc.
I expected a 50% rise to mean a 30-35% drop in revenue down to about 0.6-0.7 BTC per day, but it's been better than that. Even though the the network jumped as much as it did, the daily take on the Jupiter is still 0.75-0.85.
Your revenue is based on difficulty. Until difficulty adjusts of course you will make the same revenue. If difficulty adjusts up 50% then you will make 1/1.50 = 66% of what you were making before.