I would honestly suggest creating a copy of your project in 4.13.1 and seeing whether or not your IAP restores are working quicker or not.
Macro Documentation:
- [Macros][1]
- [Using Macro Libraries][2]
- [Making Macros][3]
- [Macro Library UI][4]
I went in and modified the Unreal Match 3 blueprint to look more similar to yours and proceeded to make a purchase. I made sure to remove the macro, as that may not be the issue on yours, as it seems the macro relates back information regarding the purchase itself - you should be able to leave that out. I did not notice any sluggishness or slowness, I also checked with others here who work with Unreal Match 3 more often and they too haven’t seen any problems with IAP or Restore IAP.
You are more than welcome to upload your project and provide it to me through a private message on the [forums][5].
Thanks!
https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/Macros/
[2]: Using Macro Libraries in Unreal Engine | Unreal Engine 5.1 Documentation
[3]: Making Macros in Unreal Engine | Unreal Engine 5.1 Documentation
[4]: Blueprints Visual Scripting Editor User Interface for Macro Libraries in Unreal Engine | Unreal Engine 5.1 Documentation
[5]: https://forums.unrealengine.com