Copy Paste fails to save on third layer master-detail-detail screen

I have customized Acumatica’s Cost Projection Screen (PM305000) as follow

It basically have added a second grid to “Revision Log” as child to “Projection Line” grid to keep the history of changes on projection lines. Also I have customized Acumatica’s standard copy paste function to copy the “Revision Log” to the new projection revisions. The method code is as follow:

        protected virtual void CreateNewProjectionWithLog(PMCostProjection original, PMCostProjectionCopyDialogInfo info)
        {
            PMCostProjection newDoc = new PMCostProjection();
            newDoc.ProjectID = original.ProjectID;
            newDoc.ClassID = original.ClassID;
            newDoc.Description = original.Description;
            newDoc.RevisionID = info.RevisionID;

            CostProjectionEntry target = PXGraph.CreateInstance<CostProjectionEntry>();

            target.Clear();
            target.SelectTimeStamp();

            newDoc = target.Document.Insert(newDoc);

            foreach (PMCostProjectionLine line in Base.Details.Select())
            {
                    PMCostProjectionLine copy = (PMCostProjectionLine)Base.Details.Cache.CreateCopy(line);
                    copy.RevisionID = newDoc.RevisionID;
                    copy.NoteID = null;
                    copy.Mode = ProjectionMode.Manual;

                    copy = target.Details.Insert(copy);
                    copy.Mode = line.Mode;

                target.Save.Press();
                foreach (UDCTPMCostProjectionRevisionLog log in RevisionLogsView.Select())
                    {
                        UDCTPMCostProjectionRevisionLog logCopy = (UDCTPMCostProjectionRevisionLog)RevisionLogsView.Cache.CreateCopy(log);
                        logCopy.RevisionID = copy.RevisionID;
                        logCopy.LineNbr = copy.LineNbr;
                        logCopy.NoteID = null;

                        logCopy = RevisionLogsView.Insert(logCopy);
                        target.Save.Press();
                }
            }

            target.Save.Press();
            PXRedirectHelper.TryRedirect(target, PXRedirectHelper.WindowMode.Same);
        }

My copy operation successfully copies Projection Document (Acumatica Table) and Projection Line (Acumatica Table) but fails to “SAVE” the Revision Log (Custom Table) . Can someone shed some light what I’m doing wrong?