Does Onkelos claim that Yaakov's zechuyot shrunk?

Summary: In other words, is he echoing Rashi and Chazal?

Post: Towards the beginning of parashat Vayishlach, when Yaakov prays to Hashem to spare him from Esav, he says (pasuk with Onkelos's translation):

לב,יא קָטֹנְתִּי מִכֹּל הַחֲסָדִים, וּמִכָּל-הָאֱמֶת, אֲשֶׁר עָשִׂיתָ, אֶת-עַבְדֶּךָ:  כִּי בְמַקְלִי, עָבַרְתִּי אֶת-הַיַּרְדֵּן הַזֶּה, וְעַתָּה הָיִיתִי, לִשְׁנֵי מַחֲנוֹת.

זְעֵירָן זָכְוָתִי מִכֹּל חִסְדִּין, וּמִכָּל טָבְוָן, דַּעֲבַדְתְּ, עִם עַבְדָּךְ:  אֲרֵי יְחִידַאי, עֲבַרִית יָת יַרְדְּנָא הָדֵין, וּכְעַן הֲוֵיתִי, לְתַרְתֵּין מַשְׁרְיָן.

Thus, he translates קָטֹנְתִּי מִכֹּל הַחֲסָדִים  as זְעֵירָן זָכְוָתִי מִכֹּל חִסְדִּין. This would seem to be declaring that as a result of all the Divine Favor shown to him, his merits have been decreased. (See Chalifot Semalot for this point.) That is, lehavdil, for each time Hashem has saved him or granted him prosperity, Mitzvah Points, sort of like Hit Points, have been deducted.

This would echo Rashi's (and Chazal's) comments on this pasuk:

I have become small: My merits have diminished because of the kindnesses and the truth that You have rendered me. Therefore, I fear lest I have became sullied with sin since [the time that] You promised me, and it will cause me to be delivered into Esau’s hand[s]. — [from Shab. 32a, Ta’anith 20b, Ber. 41]

קטנתי מכל החסדים: נתמעטו זכיותי על ידי החסדים והאמת שעשית עמי, לכך אני ירא, שמא משהבטחתני נתלכלכתי בחטא ויגרום לי להמסר ביד עשו:

This might well be true, but I am not utterly convinced of this. The phrase זְעֵירָן זָכְוָתִי is not of the form VERB NOUN -- that "have shrunk my merits". Rather, it is of the form ADJECTIVE NOUN. "are few my merits". Even without the midrash, simple peshat in the pasuk is that Yaakov is saying that he is not (and perhaps even was not) worthy of all the good that Hashem has granted him. See, too, Ibn Ezra:

לב, יא]
קטנתי -כמו גם יכלתי. 
והטעם פחות אני וקטן עד שתעשה עמי כל החסדים. וכבר פירשתי חסד ואמת.

Yes, Onkelos brings out the word zechuti, but that just makes explicit that Yaakov is talking about personal worth. It does not mean that he is necessarily talking about losing Mitzvah Points.

The derasha does not come (purely from katonti). Rather, much of it comes from the word מִכֹּל. The prefix mi- can either be one of comparison -- "I am lesser than all of the kindnesses", or else one of derivation -- "I am lessened from all of the kindnesses." The midrash exploits this ambiguity, such that while peshat is "I am lesser than", the midrash takes it as "I am lessened from." With this different selected meaning of mi-, the word katonti also assumes a slightly different meaning. Instead of "I am less than", indicating a lack of worthiness, it becomes "I am lessened", that he has lost merit points.

If so, in my humble opinion, Onkelos is not really taking a position between the peshat and the derash. After all, he translates מִכֹּל as מִכֹּל. The ambiguity is preserved in the Aramaic. And as I noted above, stating  זְעֵירָן זָכְוָתִי also indicates nothing, because it means (or can readily mean) "my merits are few" rather than "my merits are lessened".