Commission tiers: when does a scalper actually reach them?

[FXS London Scalper]

Brokers advertise tiered commissions: lower rates for higher monthly volume. The headline rate is usually the best tier, which many retail traders never reach.

Example tier structure (typical, not from any specific broker):
- Under 100 lots/month: $7 round turn
- 100–500 lots: $6
- 500–2,000 lots: $5
- Over 2,000 lots: $4

A scalper trading 20 times a day at 0.5 lots trades 10 lots daily, around 200 lots a month (counting each round turn once). That's the $6 tier.

Questions worth asking:
- Is volume counted per side or round turn?
- Is the tier applied retroactively to the whole month or only to lots above the threshold?
- Does the tier reset monthly?
- Is volume pooled across accounts?

The danger is trading more to reach a tier. If extra trades have negative expectancy, the commission saving is smaller than the trading loss.

Has a commission tier ever made a real difference to your annual costs?