Comparator cannot read from blocked chest

I was doing item splitter and it worked it used comparator to "read" when 2 items were in a doublechest it would suck them into 2 different hoppers
i was happy with it but when i had covered the chest i noticed that it had stopped i figured out that when chest was blocked it comparator wouldnt detect items inside it only happen on this setup it works like BUD

ill attach world down below where i demonstrade this

i know that its hard to understant but look this world it will show you the bug

Thanks _{latelah_FIN}