I'd like to know if you're experiencing time in a different rate than the rest of us, because on the timers it's simply evident it's nowhere near just '1 min'. If what you're actually trying to say is "Not doing wall to wall won't make the run necessarily too long." then saying "add 1 min to the run" is not a good sentence to convey that.
Let's break it down, roughly.
[First Wall Pull] > [Second Wall Pull] > [Boss]
First wall pull generally takes about 30s to 50s to mow down. The ones like Matoya's Relict can be even shorter! This assumes everybody are performing their rotation decently, including DPSing healer, and good use of toolkits. Subsequent wall pull before next boss will take -just slightly longer- because there are probably some offensive toolkits are on cooldown. By the time the group reaches the boss most if not all tools should be off cooldown. Boss generally take about 2-4m depending on the encounter.
Now, what if the party decides to do smaller pull?
[First small pull] > [Second small pull] > [Third small pull] > [Fourth small pull] > [Boss]
Again, with the same group of players. First small pull? No sweat. But now they have to do this cycle of "Faster pull > Slower pull" one extra time because for whatever reason they want a smaller pull. And don't forget travel time may also be counted here. The group stops to kill the mob four times instead of just twice.
And it doesn't stop there. We still have another factor that determine how fast a run will go: the players. Yes, it's us. You, me, they, whoever's in the party.
You get a healer that refuse to DPS? Add more time spent there. (A dpsing healer or a good tank can dish roughly about two-third of 1 decent DPS' output.)
You get a dps that just do single target attacks? Add more time spent there.
You get a freestyle player that just presses whatever button they want? Add even more time spent there!
You get a player that pretends to be present but is actually just auto attacking stuffs? Add mo-- oh wait. Just vote dismiss them and carry on with only 3 players manpower while waiting for a replacement.... yep, more time spent!