Vernon.... Let me put it another way. If there is a 360-day calendar at all in the Bible, it was probably really the 364-day calendar attested elsewhere, since that calendar was originally made up with 12 months of 30 days each. The lunar calendar was 354 days in length -- there was no such thing as a 360-day lunar calendar. It is confusing because there are 4 days which do not belong to the months (at least before Jubilees and the Qumran Essenes made them the 31st day of every third month). These days must be included in the reckoning of the year however because each year contains 52 sabbaths (it is a sabbatical calendar). The passages in Daniel and Revelation that regard each month as 30 days in length (cf. Daniel 6:7, 12, 12:11-12, Revelation 11:2-3) would have otherwise presumed this calendar since that was the one that posited the default length of the month as 30 days. The 4 extra days were originally not counted as belonging to the months but as markers of the seasons in between the months (cf. 1 Enoch 74:11, 17, 75:1-2, 82:4-6). So the solar calendar was "six" days ahead the 354-day lunar calendar when reckoned one way (1 Enoch 74:11) and "ten" days ahead when reckoned the other way (v. 14-16). But in neither case was the year literally 360 days in length, as if the epigomenal days did not exist. BTW, there is no such "prophecy" in Daniel that posits a duration leading to either 1914 or 1878. Only under a tortured interpretation of ch. 4 would such a period of 2,520 years be calculated. But if one were to calculate such a consecutive period utilizing the reckoning of the months as 30 days each, it should be borne in mind that each year of twelve 30-day months also included four additional days interspersed between the seasons.
The egg illustration would better fit this situation if you buy 5 packs of 10 eggs (instead of 6 packs of 10 as in bernadette's example) but for each pack, you get 2 extra eggs free, so even though you pay for only 50 eggs you still end up with a total of 60.