'Amendment of Pleadings' at the closing Arguments stage????

Amendment of pleadings cannot be made abruptly during arguments nor it could be allowed. If the order is based on such extraneous considerations,better file appeal there are every chances of success.

Amendment of pleadings can be done only before the trial starts and not later.

is it civil case related to property  or matrimonial case?

Even if the counsels (of either party) argued anything (as the counsel deviated from the pleadings in your case), the court cannot go beyond the pleadings while passing the orders.  The court has to stick up to the facts of the case, and travelling beyond the facts is not expected.  If the court has passed an order relying on such submissions, then such an order is erroneous, you may prefer an appeal against the said order.

As far as the oral arguments are concerned, every party has got the right to argue it's case.  The party who files an application has to argue first, then the term of opposite party comes and the party filing an application has right to reply on law points.  Normally, interruption while advancing the arguments is not expected.

it is not allowed to amend pleadings once trail is commenced as per amended Civil procedure code under Order VI rule 17 of CPC. if any party wants to amend his or her pleading they have to do it before commencement of trail but  not later. it is fit case for appeal. 

There is no restriction for amendment of pleading prior to judgement.

Parties have bonafide right to put their position before trial court and unless it is malafide , it has to be allowed.

Go to higher court if you have substantial evidence to oppose it.

The Court cannot go beyond the pleadings. The orders passed must be also specifying the reason of passing thereof.  Just compare the judgement with the application grounds / pleadings as to  whether they were in parity of the grounds of pleadings, if no you have chance to challenge and reversal.

If not satisfied to appeal., such matters end up to SC.

during oral arguments he may speak anything he wishes , but while giving judgement court works within narrow  zone of pleadings only. dont allow him to amend pleadings in writing.

After amendment to CPC pleadings amendment after trial is restricted.