The WAVA standards do not include a 4 mile table, but one can be added by using the 5 mile WAVA standard time to predict a 4 mile time, and then interpolating 5K and 8K age correction factors to obtain an appropriate age correction factor for 4 miles. The reason for doing so is that 4 miles, an oddball distance, is a common event in Central Park, because the geography of the park makes it easy to stage 4 mile races. The geometric center of 5 and 8 is about 6.3, the arithmatic center is 6.5, so I figure that splitting the difference and taking the midpoint is reasonable, and that is how I interpolate the age correction factors.
Note that my table will give different results than the NYRRC age graded score (but I believe I'm right and they're wrong).
Here's a sample calculation that illustrates why I think NYRRC are wrong. To get the correction factor for a given age, one divides the age graded time in seconds by the net time in seconds. To proceed, we need some results from a 4 mile race and the NYRRC age graded times (select M55-59).
Take the first result, age 57:
(23*60.0+19)/(27*60.0+42) = 0.84175This is less than the 5k correction factor for age 57 (0.8419)
But take a result for age 55 (fourth place):
(26*60.0 + 8)/(30 * 60.0 + 27) = 0.85823which is part way between the factors for 5k (0.8570) and 8k (0.8601). It's actually closer to the 5k correction factor (closer than you'd get even with a linear interpolation) and hence still looks wrong, but at least it's somewhat less wrong.
For people in the open age groups, it means absolutely nothing, because there are no age corrections for you. THe "gold standard" time I use is the same as the one used by NYRRC. In the above example, the 57 year old competitor's rating dropped by 0.3% when the calculation was performed using my correction factors (sorry Bob).