Picking between two chances?

So i have a system in place to where if your gathered energy greater than half of what the required is, then you have the option to level up.

At level 9, when you level up, you move into the next realm(stronger than the previous 9 levels) , move back to level 1, and basically repeat it like that. each realm has a greater chance of failure of moving into.

At the moment, it always says I break through into the second level every time, but never levels me up nor does it ever fail to level up.

ServerScript V

if TypeOfAction == "Breakthrough" then
	
	local stats = ReturnDataClient(player.Name, "Stats")
	local realm = ReturnDataClient(player.Name, "Realm")
	local level = ReturnDataClient(player.Name, "Level")
		
	if combatLog[player.Name].Cultivate == true and stats.Qi > stats.requiredQi/50 then
		local failchance
		stats.BTChance = ((stats.Qi/stats.requiredQi)*100)+stats.BTAdded
		
		if realm == 1 then
			failchance = 0
		elseif realm == 2 then
			failchance = 25
		elseif realm == 3 then
			failchance = 50
		elseif realm == 4 then
			failchance = 75
		elseif realm == 5 then
			failchance = 85
		elseif realm == 6 then
			failchance = 90
		elseif realm == 7 then
			failchance = 95
		end
		
		local pickChances = {
			{
				breakthrough = true,
				chance = stats.BTChance-failchance
			},
			
			{
				breakthrough = false,
				chance = failchance
			},
		}
		
		local endResult = {}
		for _, data in pairs(pickChances) do
		    for c = 1, data.chance, 1 do
		        table.insert(endResult,(data.breakthrough))
		    end
		end

		local chosenIndex= math.random(1, #endResult)
		local chosen = endResult[chosenIndex]
		
		if chosen == true then
			if level < 9 then
				level = level+1
				stats.Qi = 0
				print(player.Name.. " broke through into the level: "..level.."!")
			elseif level == 9 then
				realm = realm+1
				level = 1
				stats.Qi = 0
				print(player.Name.. " broke through into the realm: "..realm.."!")
			end
		elseif chosen == false then
			if level < 9 then
				print(player.Name.. " failed to breakthrough the next level.")
				stats.Qi = math.floor(stats.Qi/2)
			elseif level == 9 then
				print(player.Name.. " failed to breakthrough the next realm.")
				stats.Qi = math.floor(stats.Qi/2)
			end
		end
	end
end

Localscript

if not gameEvent and input.KeyCode == X then
	RequestActionEvent:FireServer("Breakthrough")
end

Thanks for giving it a read.