This is the meaning of "Overbooked" as per the explanation given at the end of Form 16A.
To me this means your challan amopunt is for 50,000.but the deductee details you entered are for more than 50,000 say 55,000.
Now the dept. has issued form 16A in antiicipation of balance payment from the Deductor. (Now verify this point - where is the question of deleting challan Or deleting any records.)
Coming to the point if you know any deductee make a confidential enquiry whether the amount is credited in his account i.e appearing in 26AS as in the following explanation it is clearly said that the Final credit will be reflected only if the difference of the amount is paid.
This means the Dept. wants to use different language rather than simple language which any one can understand confuse and have good laugh.
"Payment details of TDS / TCS deposited in bank by deductor have matched with details mentioned in the TDS / TCS statement but the amount is over claimed in the statement. Final (F) credit will be reflected only when deductor reduces claimed amount in the statement or makes new payment for excess amount claimed in the statement"
Please verify from the above point of view and let us know the trooth.