In financial modeling, we do not often consider the United States' Alternative Minimum Tax ("AMT"). We do so here only to expose you to the maximum complexity you will likely encounter in modeling taxes. The AMT is a parallel tax system designed to ensure that all taxpayers pay at least some minimum amount of tax. The 20% corporate AMT tax rate and 90% minimum taxable income offset are features of the AMT promulgated by the IRS. State and local taxes are deductible for the purpose of computing AMT.
The AMT has no bearing on our model because federal taxes computed the "regular way" exceed the AMT in each projected period. However, if pre-NOL taxable income is sufficiently low, the AMT will be triggered. Try hardcoding $15mm for taxable income in the first projected period to observe this. Also, note that triggering the AMT generates an AMT tax credit carryforward that can be used to offset federal cash taxes in subsequent periods. We have assumed that the MRY AMT tax credit carryforward is zero, as companies do not generally disclose this figure.
Note that the calculation of taxable income for the purposes of computing AMT may differ from the "regular way" calculation of taxable income in our model. Such differences add complexity beyond the scope of our model, and are best addressed by an experienced tax professional.