Shimshon: Was his birth while under the hands of the Plishtim or not?

The haftara of Naso begins in Shofetim 13:2 and extends to the end of the perek. As such, one pasuk is cut off from the perek. Or rather, the Christian perek divisions do not necessarily accord with the haftara unit envisioned by those who set the haftarah up.

What is that first pasuk? Shofetim 13:1:

א וַיֹּסִיפוּ בְּנֵי יִשְׂרָאֵל, לַעֲשׂוֹת הָרַע בְּעֵינֵי ה; וַיִּתְּנֵם ה' בְּיַד-פְּלִשְׁתִּים, אַרְבָּעִים שָׁנָה. {פ}ש

1 And the children of Israel again did that which was evil in the sight of the LORD; and the LORD delivered them into the hand of the Philistines forty years. {P}

There is a petucha separating it off from the rest of the perek. But then again, there was a petucha gap separating that pasuk off from the preceding section:

טו וַיָּמָת עַבְדּוֹן בֶּן-הִלֵּל, הַפִּרְעָתוֹנִי; וַיִּקָּבֵר בְּפִרְעָתוֹן בְּאֶרֶץ אֶפְרַיִם, בְּהַר הָעֲמָלֵקִי. {פ}ש

15 And Abdon the son of Hillel the Pirathonite died, and was buried in Pirathon in the land of Ephraim, in the hill-country of the Amalekites. {P}

The word וַיֹּסִיפוּ suggests some slight connection to the previous segment, and how upon his death they began to sin again. Then again, this seems to be a pattern, so maybe this intervening pasuk 1 attaches somewhat to both sections.

We are not told when Shimshon was born. Did this follow in the sequence? Shimshon might have been born during Hillel's lifetime, and only began fighting the Pelishtim and thus judging the Israelites for 20 years later on. Or during some of those intervening years. The pesukim are not clear. Perhaps we might be able to make some estimates on the basis of his parents working to arrange his marriage for him, but quite possibly not.

At any rate, Ralbag takes note of the pasuk in which the malach appears to the wife of Manoach, and tells her:

ה כִּי הִנָּךְ הָרָה וְיֹלַדְתְּ בֵּן, וּמוֹרָה לֹא-יַעֲלֶה עַל-רֹאשׁוֹ--כִּי-נְזִיר אֱלֹהִים יִהְיֶה הַנַּעַר, מִן-הַבָּטֶן; וְהוּא, יָחֵל לְהוֹשִׁיעַ אֶת-יִשְׂרָאֵל--מִיַּד פְּלִשְׁתִּים.

5 For, lo, thou shalt conceive, and bear a son; and no razor shall come upon his head; for the child shall be a Nazirite unto God from the womb; and he shall begin to save Israel out of the hand of the Philistines.'

Mentioning saving Israel out of the hand of the Pelishtim would seem to indicate that this can be dated to the era of yad pelishtim of 13:1. On the other hand, he considers seriously that the malach here is telling two messages: one, that in the first place, there would be a subjugation by the Plishtim, and two, that Shimshon would save Israel from them. If so, there is no way to decide.