诸位有知道MEGABUS 超额行李的收费政策吗？

刚预定了MEGABUS的车票，估计到时候行李应该会超标，MEGABUS规定的是一人一个行李箱（不大于50磅），和一个随身带包。假如有超额行李前提下，请问是如何收费。有朋友之前去得时候，是当场收了25刀一件超额行李。可是我刚刚仔细研究了下行李政策，发现有如下解释：
If you wish to take an extra piece of luggage, you should purchase an additional travel ticket in advance of travel. This guarantees your luggage space on the bus, which is limited. Customers presenting additional pieces of luggage without an additional passenger reservation for such at New York, Philadelphia, Baltimore, Washington DC, Boston, Atlanta and all Texas cities will be requested to pay the full walk-up fare for the carriage of additional pieces of luggage.


英语不太利索……前一句话还懂，超额行李就再买一张票就行。后面那几句的意思难道是这几个地方，都得出全额的旅行票价不？这个就差别大了……