Milestone modding help

[RenoMartin]

Trying to mod workers in workshops milestone, because I think sometimes it bugs out. Several times during playthroughs I hit 40%+ and it didn't count.
Wanted to bring it down at 20-25% and see how it goes. My code looks like this:


function Milestone_WorkshopWorkersPercent(city, 25)
local min_interval = const.HourDuration
local max_interval = const.DayDuration
while true do
local current_percent = city and city:GetWorkshopWorkersPercent() or 0
if current_percent >= target_percent then
return true
end
local interval = min_interval + MulDivRound(max_interval - min_interval, target_percent - current_percent, target_percent)
Sleep(interval)
end
end

function OnMsg.ClassesPostprocess()
PlaceObj('Milestone', {
Complete = function (self, city)
return Milestone_WorkshopWorkersPercent(city, 25)
end,
SortKey = 16000,
bonus_score = 3000,
bonus_score_expiration = 300,
display_name = T(590068197487, --[[Milestone Default WorkersInWorkshops display_name]] "25% Workers in Workshops"),
group = "Default",
id = "WorkersInWorkshops",
reward_research = 5000,
trigger_fireworks = true,
})
end


As you can see, I don't really know what I'm doing, best I could come up with after digging in documentation. What am I doing wrong and how it should look like?

P.S. I'd also like to reduce reasearch points reward to ~5k for balance reasons.