But do you not see that the coin is only more profitable if you sell it at that exact point in time

for example: monero is at $1. The price goes upto $1.50 as does difficulty so we switch to that to mine, we mine for an hour but after an hour the price goes back to $1. Unless we actually sold it we've actually accumulated less coins that are now worth less money.

What I'm looking for is something that does not include a dollar price in the equation.

The point at which anyone chooses to sell any coin is arbitrary and isn’t, at least in my opinion, a relevant measure here. Even if we had 100% consensus of everyone on the pool to sell immediately upon confirmation on the chain, we still would be price takers. A whale could jump in and take down the price of any coin. The trustee of the Mt.Gox debacle could decide to drop another $1 billion USD of bitcoin at market all at once and crush all the alt-coins in the process.

While your Monero example is accurate given the inputs you used, the two most important things to keep in mind here are 1) relativity and 2) efficiency.

Think about your example and hold price constant. Now for simplicity let’s add just one more coin into the mix, AEON. Let’s say both are at $1.00 USD but difficulty fluctuates. Monero diff is 2x Aeon in the mornings. Aeon diff is 2x Monero in the evenings. And you could even say that both Aeon and Monero difficulties are equal on Thursday’s.

The price of both coins stays at $1.00 USD all week long. So we mine these for exactly one week three different ways:

1. Monero all week.

2. Aeon all week.

3. Dynamic switching based upon the relative profitability of both coins.

Equipment and power costs notwithstanding, the cost of mining Monero is the opportunity cost of not mining Aeon, and vice versa.

Option 3 the most profitable on a relative basis and, thereby, the most efficient. If you were to sell all the coins mined after one week, you would notice that the true profit for options 1 and 2 are actually the same, while option 3 yields 86% more profit after 7 days. Actually, it also turns out that if you sold at any point in time within this given fantasy week, option 3 also guarantees that your true profit would also be the greatest (technically, at least equal to (during the first 12 hours only tho)).

If you are interested in some of the theory behind this, you might try googling “efficient frontier” and see if you find any of that worthwhile.