Platform ROAS: useful inside the silo
Platform ROAS is the return an ad account reports on its own spend, using conversions that account credits to itself. Meta ROAS belongs in Meta. Google ROAS belongs in Google.
Use it to compare creative, campaigns, or ad sets within the same account. Do not use two siloed multiples as though they were one shared cross-channel truth.
Blended ROAS: one numerator, counted once
When Meta and Google run together, blended ROAS uses total real revenue divided by total ad spend across those channels. The revenue numerator comes from the store, Stripe, or another processor, not from adding platform claims.
One sale in the bank means one count in the numerator. That is why the blended figure holds when the silos disagree.
MER: efficiency language, same honesty
MER is a business-level efficiency view: revenue against marketing spend, counted once. If a MER sheet still adds Meta claimed dollars to Google claimed dollars, it has renamed the problem rather than fixed it.
There is no universal good MER. Margins, fit, and channel mix decide what healthy looks like for a client.
A practical revenue hierarchy
Trust platform ROAS for what to change inside that ad account. Trust payment or store revenue for how much money arrived. Use blended ROAS or MER when you need one program-level efficiency figure built from payment truth.
Payment-verified ROAS is not a claim about multi-touch model depth. It is a reporting rule: do not present summed platform claims as the revenue line.
When a Sheet is enough
For a small book with a trusted weekly blended tab, a careful Sheet can be enough. The need for a new tool is not automatic.
The workflow starts to wobble when QBRs keep turning into “why does this not match Stripe?”, or the client needs the same live number you use. That is the agency reporting job: a live, payment-verified number both sides can open. Agency is $79/mo for up to 10 clients.