Custom Column if statements returning inconsistent results

I am attempting to create a custom column classifying count values into ranges of specified interest via the following:

if [count] = null then "< 2" else 

if [count] < 2 then "< 2" else 

if [count] >= 2 and [count] <= 3 then "2 - 3" else 

if [count] = 4 then "4" else 

if [count] >= 5 then "5 +" else ""

However, the results being returned are inconsistent at times. The vast majority of values are correctly assigned to the required ranges, but at times I am noticing counts of various amounts getting classified incorrectly such as 12 and 8 falling into "4" or a count of 8 falling into "2-3". 

I'm fairly new to PowerBI and am uncertain on the approach to take from here.