נ וְחִשַּׁב֙ עִם־קֹנֵ֔הוּ מִשְּׁנַת֙ הִמָּ֣כְרוֹ ל֔וֹ עַ֖ד שְׁנַ֣ת הַיֹּבֵ֑ל וְהָיָ֞ה כֶּ֤סֶף מִמְכָּרוֹ֙ בְּמִסְפַּ֣ר שָׁנִ֔ים כִּימֵ֥י שָׂכִ֖יר יִהְיֶ֥ה עִמּֽוֹ׃ נא אִם־ע֥וֹד רַבּ֖וֹת בַּשָּׁנִ֑ים לְפִיהֶן֙ יָשִׁ֣יב גְּאֻלָּת֔וֹ מִכֶּ֖סֶף מִקְנָתֽוֹ׃ נב וְאִם־מְעַ֞ט נִשְׁאַ֧ר בַּשָּׁנִ֛ים עַד־שְׁנַ֥ת הַיֹּבֵ֖ל וְחִשַּׁב־ל֑וֹ כְּפִ֣י שָׁנָ֔יו יָשִׁ֖יב אֶת־גְּאֻלָּתֽוֹ׃
50 He shall compute with his purchaser the total from the year he gave himself over to him until the jubilee year; the price of his sale shall be applied to the number of years, as though it were for a term as a hired laborer under the other’s authority. 51 If many years remain, he shall pay back for his redemption in proportion to his purchase price; 52 and if few years remain until the jubilee year, he shall so compute: he shall make payment for his redemption according to the years involved.
I was wondering why the Torah needed to write verses 51 and 52, as it seems self understood the message of the verse from verse 50 alone. I was referred to the Haamek Davar, although I do not understand his answer.
Could anyone either explain his answer or offer(/find) another?