Dynamic If for a button to choose the package

Question

I have a calculation where I give the user an advance option to choose a variable, PV. If the user chooses not to use the PV, the button calls the package without PV and the other way around. Here is what I did:

Panel[
  Column[{
    Row[{
      Checkbox[Dynamic[Apv], {False, True}], 
      Style["PV", 12, Black, Editable -> False], 
      InputField[Dynamic[PV], Number, Enabled -> Dynamic[Apv], FieldSize -> 5]
    }, Spacer[5]],
    Grid[{{
      Button[
        Style["Calculate", 14, Green, Editable -> False], 
        { calmessage = Style["Calculation started", 14, Red],
          Print[Dynamic[Apv]]; 
          If[
            Dynamic[Apv] === True, 
            Print[a]; Res2 = INT1DTF`MainD1I[u, PV], 
            Print[b]; Res2 = INT1DTF`MainD1I[u]
          ];
        };
        calmessage = Style["Calculation finished", 13, Blue]; , 
        Method -> "Queued", 
        ImageSize -> {350, 40}
      ]
     }, {
       Row[{
         InputField[Dynamic[calmessage], FieldSize -> {30, 1.5}]}, 
         Spacer[15]]}}, 
    Frame -> True]}]]

Apv allows me to understand if the user wants to use PV or not. And I have an If statement for the button to act accordingly. I use Print[Dynamic[Apv]] , Print[a] and Print[b] to see where the if statement goes. And it always goes to b. Any ideas what is missing in here?

When I toggle from checked to unchecked Print[Dynamic[Apv]] this changes. So I know I am reading Apv right.