questions about named UCSs

(I found a bug in my apps) I have this lines:

With ThisDrawing
Set oldUCS = .ActiveUCS
.SendCommand "UCS New View UCS New X 180" & vbCr
End With

At a certain point, the macro works no more. I noticed at long last that SendCommand creates and saves a new UCS, and names it, say, “_Active1†(if there is already an “_Active1â€, it may be “_Active2†and so on).

Oddly, if I do NOT move or change the current UCS while drawing, I can call my macro whatever times I want, even having changed the point of viw: my macro always uses the same name, say, “_Active1†again. But if I move or change the current UCS, a recall to my macro makes SendCommand create a new saved UCS, say, “_Active2â€

It seams to me that the previous UCS (I mean the current UCS *before* calling the macro) causes the macro creating (or not creating) a new named UCS.

With my current settings, when I reach 14 saved UCS, the line .SendCommand "UCS New View UCS New X 180" & vbCr makes the macro crash.

My prog ends restoring the current UCS:
ThisDrawing.ActiveUCS = oldUCS

So my questions:
why does SendCommand save that temporary UCS? How could I delete that temporary UCS?