# Carry back and forward losses: can I utilize an year I utilized already?

I am doing this study where I need to calculate the benefits of carrying back and forward net operating losses (NOLs) besides other. Following the literature, I use a simplified framework in which a firm with a NOL at year $$t$$ can carry it back to years $$t-3,t-2,t-1$$ to basically get a refund and in case the loss is not offset, it can decide to carry it forward to years $$t+j, \ j=1,2,...,18$$. It is not important if this is really the case, I am aware there are further details about the procedure but as I mentioned, it is a simplified framework. My question is the following:

Imagine in year $$t-3$$ I have a positive taxable income of 50, in $$t-2$$ it is -50, in $$t-1$$ it is 50 again and in $$t$$ it is -50. Now, say also at $$t-5, t-4$$ I have a taxable income of zero (alternatively: the firms was not born yet). Now, according to the IRS rules mentioned above, the firm can carry back the loss in $$t-2$$ to year $$t-3$$ and get a refund. In year $$t$$, it will decide also to carry back the loss. Now: can it still carry back the loss to year $$t-3$$ although it was "used up" by the NOL in period $$t-2$$? I know it might sound strange, but I was thinking it that would be possible because the refund that one would get in year $$t-2$$ is relative to the NOL in $$t-2$$ while at $$t$$ th refund would be for year $$t$$. I understand it is more natural to think that once "exhausted", a previous year with positive income cannot be used to carry back the loss again to that year; however, I would like to hear someone's opinion about it so that I can confirm or not my view.