Channel number entry timing adjustable?

I've got a universal remote set up via FLIRC so I can enter channel numbers directly into Channels running on Nvidia Shield. This is a red line feature for SWMBO. She is old school and likes to have a list of her favourite Channel Numbers especially when she is getting used to a new system.

What we have noticed though is that when you enter the digits you have to be pretty quick or the system takes your first 1 or 2 digits and thinks that's it. So, if you are entering say channel 103 and you are even slightly sluggish entering the "3", you can end up at channel 10 with a 3 on the screen.

Is there a setting anywhere that will increase the delay before it presumes you have finished entering? I had a look in what I thought were the obvious places and couldn't find one.

It's not adjustable but could be increased. How long should it be?

Not sure, without being able to test at different values

Maybe half as much again as it currently is?