Zoho Creator | Auto Number

Zoho Creator | Auto Number

Hi this is working but is it possible don't update the one autonumber field if it's not selected. 

latestDP = Client_Submit_Card[ID != 0].maximum(DP_Auto_Number);
latestJSP = Client_Submit_Card[ID != 0].maximum(JSP_Auto_Number);

vendorsValue = input.Vendors;

if(vendorsValue == "Joseph")
{

newJSPValue = ifnull(latestJSP,0) + 1;
input.PO = "JSP" + newJSPValue;
}
else if(vendorsValue == "DePrince")
{
// Calculate new value for DP_Auto_Number
newDPValue = ifnull(latestDP,0) + 1;
input.PO = "DP" + newDPValue;
}
else
{
 
input.PO = "";

}