skill code question

I've inherited a Skill script to check for missing backdrilled vias in a .brd file.  For example, given a list of net names, it will check that the backdrills on their signal vias have a stub length of a specified max length.  It reports a list of all via stub lengths and determines if the lengths are under or over the specified max length. 

The script works correctly except for vias that are VIPPO i.e. vias under a BGA without a dog bone, or vias located in the pad of a dc blocking capacitor.  For trace routes with these types of vias, the script does not work since it is expecting all vias to have a breakout trace on either top/bottom or a signal layer.  I'm trying to fix the script but I am not experienced in Skill.

The script consists of several functions - one of these is listed below.  The function looks at a via and uses the axlDBGetConnect function to return what is connected to that via. It works for vias that have a surface dogbone but for VIPPO it only "sees" the stripline routing attached to the via.  

For example, the lines below are from a via with a top layer dog bone and the via connects to sig_L5.  The script handles these vias correctly as it returns the Via connect layers as "top" and "Sig_L5". 

The script then calculates correctly the backdrill stub length for this via. 

This next example is from a VIPPO case - the via is part of a BGA footprint and the script reports that it connects to layer L5_S2, but the script doesn't recognize the Top layer pin connection.  

Is there a way I can modify the Skill function below to interpret the Top layer as well as the signal layers, as being connected to the via?  I've read about the axlDBGetConnect()  function in a Cadence SKILL reference manual but it didn't help me resolve my question. 

defun( list_layers_on_via (thisVia)
; returns all layers connected to a via
pathlist = axlDBGetConnect(thisVia) ;returns everything connected to the via, see pg 342 of the oct. 2012 skill reference
layerlist = pathlist~>layer ;paths have a layer method
layerlist = unique(layerlist) ;return value -- a list of the unique layers attached to the via
)

The   list_layers_on_via   function is called as part of a loop below.  netids = all the nets to be checked, via_list = all the vias on a given net. 

foreach( net netids
via_list = list_vias_on_net(net)

foreach( via via_list
via_layers = list_layers_on_via(via)