Malbim: The first two times it said that he will thank for the miracle done for him then, even though if two miracles were done for a person, when he blesses for one, he must bless also for the other, like it says in Brachos ¹ . After leaving jail, he should have mentioned salvation from the Midbar - however, he did not yet recognize Hashem's Chasadim - "Evilim mi'Derech Pish'am" (verse 17). Now that he was saved three times, he thanks for all of them and tells also about the first ones. Also, now he brings Korbanos Todah, also for the first salvations, for which he did not thank properly.