Plan Termination - Short Plan Year

Let's say that there is plan that defines a plan year as 1/1 to 12/31. The limitation year is based on the plan year, so if the plan is terminated, the 415 and 401(a)17 limits will be pro-rated. What if the plan terminates of 3/2/2017? How would the limits apply? Specifically, since the plan terminated during the month of March, should be limits be:

1) 270,000 * (3/12) and 54,000 * (3/12) for 401(a)17 and 415, respectively.

or,

2) 270,000 * (61/365) and 54,000 * (61/365) for 401(a)17 and 415, respectively.

Basically, when the pro-rated computation is done, is it based on the number of months or the number of days?

Thanks in advance.

A reading from the book of Regulations

Section 1.415(j)-1(d)(2)

.....multiplying the applicable dollar limitation for the calendar year in which the limitation period ends by a fraction, the numerator of which is the number of months (including any fractional parts of a month)...

to make it fun 1.401(a)(17)-1(b)(3)(iii) simply says

the numerator of which is the number of months in the short plan year, the denominator is 12

(no mention of using fractional periods)

of course every example I have ever seen always had a plan year ending at the end of the month.