Google Sheets - duration between two specific times

I'm having a little trouble writing a formula to measure duration between two specific times within a time range.

i.e. 1300-1700

Total hours=4

Hours between 1530-1800=1.5

So far I've only managed to measure total duration between two times adjusting for past midnight with Total hours=1700-1300+(1700<1300)

I've trawled the net and attempted some IF functions to no avail. Below is a quick example.

Example spreadsheet: https://docs.google.com/spreadsheets/d/1QY4o7RMkWGcZPNUZg5OAETtmmlm07E6yyFjFnu0Jgac/edit?usp=sharing

Any help is much appreciated!