"The word used for "weeks" is actually TWO words in the original text: shibah and shabuwa."
In his book "Daniel, Key to Prophetic Revelation," John Walvoord cites Edward Young's "The Prophecy Of Daniel", which noted that Daniel used: "the masculine plural
instead of the usual feminine plural. No clear explanation is given except that Young feels 'it was for the deliberate purpose of calling attention to the fact that the word sevens is employed in an unusual sense.'" This word is found only FIVE times in the O.T., all in the 9th chapter of Daniel, twice in verse 24, twice in verse 25, and once in verse 26. Interestingly, Daniel's verse 27 uses "shabuwa"
However, if you examine a J.P. Green interlinear, you should find FIVE instances of the Hebrew word "shibiym" ("Strong's" 7657), and TWO instance of "shabuwa". According to "Strong's", "shibiym" is described as a "multiple [plurl] of 7651", which is the word "sheba" in feminine gender and "shibah" in masculine gender. "
If I understand the contexts correctly, it appears that the first sixty-nine "shibah" are one chronology, and the seventieth "shabuwa" is a different chronology. It seems fairly obvious that the seventieth "shabuwa" is a seven-year period, and that the sixty-nine "shibah" are NOT. Nearly all commentators interpret all seventy periods of time as "shabuwa", which totals to 490 years. Literal scripture does NOT support that interpretation."