Mike,
Per their web site, Texaco/Chevron ELC contains SCAs so no filter is needed. I would check with BCS and find out what they used and continue with it rather than add differing ELCs if you have to "top -off"in the future. Per Texaco's data their fluid is good for 8 years or 750K miles. Interestingly, they do not say their fluid meets Cat's EC-1 or ASTM D4895 specs, so not sure I would mix Cat ELC fluid with it. Most extended life coolants contain SCAs (e.g. Mobil, Fleet, etc) but one needs to check this and also verify it is compatible with what you already are using.
Steve