Neither the Gaza Ministry of Health, nor the armed wing of Hamas have released the number of combatant casualties, leaving the IDF's number as the only estimate available. If that estimate is incorrect, they could and should challenge it by putting forth their own.
The source you provided says "for every junior Hamas operative that Lavender marked, it was permissible to kill up to 15 or 20 civilians". This is clearly an upper bound, and makes no claim about how close to this they actually come.
In the same way, I might offer my customers an SLA of two nines in their contract, but never drop below three in practice. Part of effective planning is describing the worst case scenario, but that doesn't imply it will actually happen.
The source you provided says "for every junior Hamas operative that Lavender marked, it was permissible to kill up to 15 or 20 civilians". This is clearly an upper bound, and makes no claim about how close to this they actually come.
In the same way, I might offer my customers an SLA of two nines in their contract, but never drop below three in practice. Part of effective planning is describing the worst case scenario, but that doesn't imply it will actually happen.