3Rd function

[maddog2020]

I have a JD 4720 that I want to add a grapple to. I already have a power beyond on my tractor I use to operate a backhoe. I purchased a 3rd function kit from Summit hydraulics. I was told to connect power beyond port to "P" port on valve from T port go to current power beyond inlet and take other side of PB to tank> that makes sense since you are just making a loop. What doesn't make sense is my power beyond has 1/2 hoses. The ports on the 3rd function block have 1/2 orb threads but the hole going through the block is maybe 1/4. They told me this will not restrict flow. How can going from 1/2 to 1/4 inch not restrict flow?