Pro version: less than not working & between?

Hi, I have the pro version so that I can use the operators. Right now > and >= are working just fine. However, less than and < and <= are not working. It is putting these conditional fields back to = functions.

show [group-nobmi] if [bmi] is empty “0”
show [group-bmi-status-underweight] if [bmi] equals “19”
show [group-bmi-status-overweight] if [bmi] > “25”
show [group-bmi-status-normalweight] if [bmi] is empty “19”
show [group-bmicounsel] if [bmi] > “25”

Also, I need a between operator. Is this possible? For example, normal BMI is between 19 and 25. How can I create a conditional field that would show a group for this range of answers?