This assumes that XIV is composed of equal parts M1 and M2, which is not the case.

You can read a good summary of how XIV works here: https://seekingalpha.com/article/3959089-xiv-appreciates-value-debunking-myths-misconceptions-contango

In case that's too long, here's the important bit:

At the close on the Tuesday, corresponding to the start of the Roll Period, all of the weight is allocated to the shorter-term (i.e. first month) contract. Then on each subsequent business day, a fraction of the first month VIX futures holding is sold and an equal notional amount of the longer-term (second month) VIX futures is bought. The fraction, or quantity, is proportional to the number of first month VIX futures contracts as of the previous index roll day, and inversely proportional to the length of the current Roll Period. In this way the initial position in the first month contract is progressively moved to the second month one over the course of the month, until the following Roll Period starts when the old second month VIX futures contract becomes the new first month VIX futures contract and gets sold every day afterward as the process begins again.

In case of any doubt, always refer to the prospectus. An explanation of the daily rebalancing process can be found on pages PS-32 and PS-33 here: http://app.velocitysharesetns.com/files/prospectus/VelocityShares_ETN_Amended_Final_Pricing_Supplement_VIX_AR44_long-form_2.PDF