On the FederalInstalment worksheet, TaxCycle is calculating the instalment payment method (monthly vs. quarterly), based on the incorrect year. In the section titled "Monthly vs. quarterly instalment payments," TaxCycle is using amounts from the "previous year" when the selection is made to use the "current year." It is also using amounts from the "second previous year" when the selection was made to use the amounts from the "previous year."
If you are preparing an Alberta AT1 return, please also see the Known issue affecting the calculation of the AT1 instalment exemption.
Background
For federal instalments, a small CCPC is eligible to make quarterly instalment payments if, at the time the payment is due, it meets various conditions. One condition requires that a corporation must have claimed a small business deduction for the current or previous tax year. On the FederalInstalments worksheet, this question is shown in the "Monthly vs. quarterly instalment payments" section:

In this context, “current tax year” should refer to the tax year for which instalments are calculated. “Previous tax year” should refer to the tax year of the return you are working on.
If you are preparing a T2 return for a 2017 calendar tax year, the term “current tax year” mentioned in the Federal Instalment Worksheet refers to the next tax year of 2018. However, TaxCycle incorrectly calculates the answer to the above question by interpreting the “current tax year” to be 2017.
Similarly, the term “previous tax year” refers to 2017, but TaxCycle incorrectly calculates the answer to the above question by interpreting the “previous tax year” to be 2016.
Workaround
Answer the question based on the meaning described above, interpreting "current tax year" to mean the tax year for which instalments are calculated. Please also review the resulting calculations and override as necessary.
Resolution
This issue was resolved in version 7.2.33731.0.