AML reporting on micro-transactions, where's the line?

I'm still wrapping my head around the nuances of AML reporting, especially concerning international transactions. We have a growing client base doing a lot of smaller, frequent transfers across borders, think $20-$100 amounts for digital services. Individually, these are negligible, but aggregated for a single client over a month, they can start to look interesting. Our current threshold for 'suspicious' is a bit vague on the cumulative side for these micro-transactions. Are other firms setting hard cumulative caps for reporting, or is it more about the pattern recognition regardless of total sum? Trying to avoid both under-reporting and drowning in unnecessary paperwork.