Weird anomaly when using Docking Port Jr.

[Azamorn]

I've been building a station in LKO that is going to land on the Mun, I'm not that far into the tech tree yet so I've been attaching modules with the docking port jr. 
Everything went fine with putting it together in orbit, have 4 modules attached that gives me atleast 3000 units of fuel. The problem I'm seeing is that Mechjeb and Kerbal Engineer Redux is not taking the fuel from the modules into consideration when calculating the DeltaV, While i should be having easily 3000 dV or more it's only displaying 200 dV, as a work around I'm using the TAC Fuel Balance mod to get fuel into the main tank.

Anyone else experienced this issue before?

[Perry Apsis]

I suppose as a matter of form I should ask whether you clicked the "disable crossfeed" button on the ports. It defaults to enabled, but it's worth checking. Also worth checking is whether you have any separators or decouplers between the ports and the rest of the ship (crossfeed defaults to disabled on those).

 

[Malich]

Or enable staging. If the staging of the pods happens before the engine it won't count it 

[Norcalplanner]

You have to upgrade one of the KSC buildings to enable resource transfer - can't remember which one at the moment.