Take a look at the Reconciliation Report for the Local. This report shows you how the PCT and DBF charges are applied and why there may be variations from Month to Month. Check out this Knowledge Base Article if you have questions on viewing this report.
Sometimes the reason PCT Charges are so low is that there were members that dropped. For each Dropped Member the Local received 7 months PCT Credit, which is why the PCT totals were so much lower. Other times it could be that there were several members that Initiated, if those members were Regular, the Local is charged 6 months Per Capita in advance, which would cause the PCT Charges to be larger.
We would also suggest reviewing the Flow Report which shows the activity changes throughout a month or multiple months.
Each of these reports together will paint a picture of why the Per Capita Charges are the way they are.