Students who continue pursuing rigorous coursework will remain competitive in the college admissions pool even for the most competitive application processes. This is because admission policies are not based on the number of college preparatory credits, such as AP, Cambridge, College in the High School, Running Start, CTE, etc., students earn in high school, rather admission considerations are based upon whether the student took advantage of what the system offered in addition to how the student performed in these classes. More can be read about college admissions here.
In some ways, by offering the 7th-period, we positioned students to increase workload by taking additional coursework that may be unnecessary and ultimately unhelpful in the overall college admission process. The committee looked at AP course history over time as a proxy for this question, and indeed we have seen an increase in students taking multiple AP courses in place of electives with varying degrees of success and impact.
Additionally, many school districts in the region and across the state never moved to a 7-period day, largely due to the unfunded cost associated with that model and have continued to offer 6-period high school schedules. Colleges and universities, including those with very competitive application processes, take this into consideration as part of the process.