It's just the plain reading of the text. Your interpretation can't stand. Textually. Or according to Judaism. That's why I challenge you to come up with proof. I haven't ever seen any. Maybe there is. Maybe you know of some. But what you posted, actually disproves your assumption. It says one Rabbi challenged many Rabbis and the many Rabbis understood it the way I presented it - the way the text plainly reads.
I know you are very invested in understanding it according to 50 year sets. But that is not the way the text reads. That's just the way it is.
The Gemara answers: Come and hear, as it is taught in a baraita that there is a dispute between Rabbi Yehuda and the Rabbis: The verse states: “And you shall sanctify the fiftieth year” (Leviticus 25:10), from which it is derived: You count it as the fiftieth year, i.e., the Jubilee Year, but you do not count it as both the fiftieth year and the first year of the next Sabbatical and Jubilee cycles. From here they stated: The Jubilee Year is not included in the counting of the seven-year cycle of the Sabbatical Year. Rather, the year following the Jubilee Year is considered the first year of the next seven-year cycle.
Babylonian Talmud Nedarim 61a:4