Why did Yakov ask for a favor from Yosef instead of commanding him?

Question

Gen 47, 29:

"וַיִּקְרְבוּ יְמֵי־יִשְׂרָאֵל לָמוּת וַיִּקְרָא לִבְנוֹ לְיוֹסֵף וַיֹּאמֶר לוֹ
אִם־נָא מָצָאתִי חֵן בְּעֵינֶיךָ שִׂים־נָא יָדְךָ תַּחַת יְרֵכִי
וְעָשִׂיתָ עִמָּדִי חֶסֶד וֶאֱמֶת אַל־נָא תִקְבְּרֵנִי בְּמִצְרָיִם׃

And when the time approached for Israel to die, he summoned his son Joseph and said to him, “Do me this favor, please, place your hand under my thigh as a pledge of your steadfast loyalty: please do not bury me in Egypt."

Seemingly, Yaakov should have commanded Yosef to bury him in Israel, but instead, he begged him.

Why?

Answer 1

R' Samson Raphael Hirsch, in his commentary on this verse, reads the first נא as "after all." He suggests that Yosef had always wanted to use his power as viceroy to do favors for his father, but Yaakov had refused special treatment. Now, Yaakov did finally want one special favor, so he opened with "if, after all, you still want to favor me."

Taking this idea in a slightly different suggestion, I would suggest that perhaps even now, Yaakov was trying to avoid taking unfair advantage of being the viceroy's father. So, he approached Yosef as a petitioner to the viceroy, using appropriately obsequious language, rather than as a father to a son.