I hope this isn't true. The limits of cloud DVR storage was stated in https://customer.xfinity.com/help-and-support/cable-tv/x1-dvr-overview/ as 60 HD or 300 SD but this was in mpeg2 days.
An HD mpeg4 takes about 1/2 the space of an mpeg2 so of course we assumed that as the conversion to mpge4 progressed that effective storage would increase and it did. However, it appears that the Cloud DVR gods have decided to limit cloud DVR space not to 'size' but to hours (in this case 60 hours per DVR) of storage and not by size. The effect of this is now showing up in other threads where 'mysteriously' the cloud DVR is full but the local DVR has plenty of room. Hopefully somone will clarify this for us (confirm/correct/ or say it is wrong information).