Time limit games

[JPaco54]

My issue with times games is not what the official start time is but when does the game end. All tournament youth competitive games that I have umped are timed, except for the final championship game. The bigger issue to me is when does the game officially end. Rules state: "1 hour and 40 mins. or 6 innings which ever comes first. Complete game after 4."
Example - Home team is winning after 5 innings, third out made by home team with 30 seconds remaining. Do you start another half inning with the visiting team coming up to bat? This will push the game time well past the 1hr. 40 mins. If VT ties the game then you have another half inning to play giving the HT another at bat. So, does the game end before the VT takes the field. Some tournaments state, if there is any time left after the third out is made by the HT and HT is winning you must continue play with the VT coming to bat. So, if there is 30 seconds or 1 minute left after the third out, you know the next pitch will not start until another 2 -3 minutes have past so now you have passed the 1 hour 40min time frame to start another inning. This is where many of the coaches start playing games as you know, to either stall or speed up the game so another inning will not start or forces you to start another inning. Are there any less complicated ways to handle this and being fair to both teams?