How can I modify the shipping delivery date on the checkout?

[DutchDelight]

I want to increase the estimated delivery date by 1 day.

So instead of "2 business days" it would say "3 business days", as delivery carriers aren't that reliable.

I have looked at the "checkout language"-method, but was not able to add 1 to the {{count}}. I've tried count+1, count | plus:1, anything really, but then it would always come back as the code itself on the page, instead of a number.
Yes, I can put "Estimated: " in front of it, but it would do this for EVERY SINGLE ONE of them, which isn't really what I want, as it would be ugly.

Is there anything else that could be done? (outside of changing it completely to a delivery date)