People cost should be split by department, and Cost of Sales should include all costs relating to service delivery.
This means it's unlikely you have an accurate picture of your Gross Margin - a crucial metric for SAAS companies.
This is a common problem, and often leads to difficulties in raising investment / running out of cash when trying to scale.
It sounds likely you are doing this right!
It's really important to do regular, accurate cashflow forecasts.
If not, you'll likely either:
Grow slower than you otherwise would - because you're not confident enough to invest, or
Run out of cash sooner than you expect
If not, you'll risk:
Growing slower than you otherwise would - because you're not confident enough to invest, or
Running out of cash sooner than you expect
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