status/FreezeShootStatus.cs
using System;
using System.Collections.Generic;
using System.Linq;
using Sandbox;

[Status(5, 0, 1f, 0, false )]
public class FreezeShootStatus : Status
{
	public FreezeShootStatus()
    {
		Title = "Chilly Bullets";
		IconPath = "textures/icons/freeze_shoot.png";
	}

	public override void Init(Player player)
	{
		base.Init(player);
	}

	public override void Refresh()
    {
		Description = GetDescription(Level);

		Player.Modify(this, PlayerStat.ShootFreezeChance, GetAddForLevel(Level), ModifierType.Add);
	}

	public override string GetDescription(int newLevel)
	{
		return string.Format("{0}% chance for your bullets to freeze on hit", GetPercentForLevel(Level));
	}

	public override string GetUpgradeDescription(int newLevel)
    {
		return newLevel > 1 ? string.Format("{0}%→{1}% chance for your bullets to freeze on hit", GetPercentForLevel(newLevel - 1), GetPercentForLevel(newLevel)) : GetDescription(newLevel);
	}

	public float GetAddForLevel(int level)
    {
		return 0.02f + 0.06f * level + (level == 5 ? 0.03f : 0f);
    }

	public float GetPercentForLevel(int level)
	{
		return 2 + 6 * level + (level == 5 ? 3 : 0);
	}
}