Modeling seller's rollover equity in a roll-up

I have a question regarding how the equity for selling entities is typically treated in a search fund that is executing a roll-up. Do you essentially just sum up all of the equity contributions and then adjust them for dilution from the searchers’ equity? 

For example, $100 in search capital is used to acquire five separate companies for $80 each. Each $80 purchase is funded with $50 of debt, $10 of rollover equity, and $20 of search capital. That means there was $100 of search capital plus 5 × $10 = $50 of rollover equity. The search capital providers would have $100 / $150 = 67%, and then 67% × (1 − 20%) = 53%. The sellers’ rollover equity would be $50 / $150 = 33%, and then 33% × (1 − 20%) = 27%. The searchers would have 20%, so 53% + 27% + 20% = 100%.

Is that how it would typically work? If not, how would it usually be structured?