Score on fit and on value separately, then tier on the combination. A Tier 1 should mean high fit and high value, not just a big logo. Publish what moves an account between tiers and what triggers a re-score, or the tiers freeze and reps stop trusting them.
Keep the scoring logic in the enrichment layer rather than hard-coded in the CRM, so it can be re-run against fresh data. Feed the tiers into routing, territory and outbound prioritisation — a tier that doesn't change what anyone does is decoration.
Every claim above comes from work LeanScale published. These are the sources.