Help charting multiple item progress over time

[GJF36]

I am trying to develop a front end Report that charts the Design progress of 2 Sites with multiple Plants in each site over a set period of time.
The data is obtained via DataLink from individual Progress Reports (Number of Connected Cables & Number of Connected Loads) as compared to one of two standard base plants
Basically I want to chart the 'Design Total % Completion' of a Plant once it is replicated in the database over a given period of time.
There is some conditional formatting to help with visual clarity (Unused Cells Grayed Out, Today() Highlighted in Yellow etc)
In my Progress Calender I have the following Formula
=IF($C5="","",IF(CG$1<$B5,"",IF(AND(CG$1=TODAY(),$C5>0,$J5=""),$L5,IF(AND(CG$1=TODAY(),$J5>$L5),$J5,"")))), Where;-
$C5 = Name of Plant
CG$1 = Calender Date
$B5 = Plant Start Date
$J5 = Completion %
$L5 = Default Completion % (Assigned as a minimum % when the plant is copied in the database)

Chart_Screen Shot.JPG

The object is not to start monitoring a Plant until it has a 'Date Started' value
Am having trouble getting the values to stick, as when the date progresses, values from the previous day are returned to 0 (Zero) (as in 09...11-Nov)
Have resorted to manual entry (Up to 08-Nov) until I can get sorted. Bit new to VBA but would be happy to implement a VBA solution