In-Game Currency [Developer Products] Please Help?

In my game, I have made a currency called "RoCash." This currency will be used to purchase things in the game.

The Value of "RoCash" is inserted into the player each time they enter the game. A Data Persistence script automatically saves the state of the value each time it has changed. (I am not using DataStore for a reason...)

Okay, I have a Shop GUI, and in the GUI, there's a button that is supposed to add 5 RoCash to the player's RoCash value each time it's purchased...

The Product works just fine. However, adding the RoCash does not. As you can see below, I want the player to receive 5 RoCash. When the product is purchased, it gives the player 20 RoCash... Why? How can I fix this?

Server-Side

local Player = script.Parent.Parent.Parent.Parent.Parent.Parent

local MarketplaceService = Game:GetService("MarketplaceService")

MarketplaceService.ProcessReceipt = function(receiptInfo)

    Player.RoCash.Value = Player.RoCash.Value +5
    wait()
    Player.PlayerGui.Purchases.RoCash.Visible = true
    wait(5)
    Player.PlayerGui.Purchases.RoCash.Visible = false

    return Enum.ProductPurchaseDecision.PurchaseGranted     
end

Client-Side

local buyButton = script.Parent
local productId = 19192652
local Player = script.Parent.Parent.Parent.Parent.Parent.Parent

Type = 0

if Player.Name == "Bolohuc" then Type = 2 else Type = 0 end

buyButton.MouseButton1Click:connect(function()
    Game:GetService("MarketplaceService"):PromptProductPurchase(game.Players.LocalPlayer, productId, false,  Type)
end)

PLEASE ANSWER AS SOON AS POSSIBLE!

NOTE: I don't want you to change the script unless it's causing the problem... It works fine other than the adding RoCash. Please help me... Provide details with your answer please.