Flexible time is an Artistic License taken by the creators, and is generally considered acceptable since it serves to narrate the story better, and this is quite common. Quoting TVTropes:
Creators are allowed to be inaccurate if the inaccuracy serves the
story better than accuracy would.
This feels unusual for anime adapted from the manga. In the manga, the panels are not proportional to real life time. You can use more panels to describe some events in more detail compared to others, even though they may occupy the same amount of time. In the anime, however, the frame duration is proportional to real life time, but the narration should follow the manga, which leads to this anomaly.
In the examples you mentioned, if the anime creators had to keep the times realistic, they would not be able to convey the same detail that Kishimoto-sensei included in the manga, which would make for a poorer viewing experience.
To elaborate on that point, there is another example near the start of the series, when Naruto and Sasuke team up to rescue Kakashi from Zabuza's Water Prison. Naruto then spends about 5 minutes explaining what his plan was, while Kakashi and Zabuza wait! That is entirely impossible in a real battle, but without it, the viewers would have no way of knowing what happened, and it would not be interesting to watch.