AMA - Demystifying HubSpot's lifecyle stages, deal stages and lead status

Frank,
When we generate a lead that turns out to be an existing customer, I’m temped to mark them as a customer but worried that might mess-up the reports and analtyics.
Background:
I’m generating net new leads and tracking results in HS.
Existing customers are tracked in a different CRM but often we find we get a form fill from a current customer (which would become in upsell lead); something we don’t track in HS.