1. The raga I sang was S G M P N / S N D P M G R in the 22nd mela. The historical documentary evidence about this scale shows that this was called Devangandhari. Please not that originally it was not called Devangandharam or Karnataka Devagandhari as perceived by some. The scale is also the exact counterpart of the North Indian raga Bimpalas.
2. Abheri as per historical documentary evidence, is the same scale S G M P N / S N D P M D R in the 20th mela. Many musicians and musicologists have said in the past and continue to say that this was the raga in which Nagumomu was composed by Tyagaraja but the change to its present form was brought about and popularised by Musiri Subramaniya Iyer through his immortal 78 rpm record.
3. The 22nd mela janya scale could not be referred to by its 'original' name Devagandhari becasue of the presence of the more popular Kshirasagara and their like. This more popular Devagandhari was a completely different raga. So how could you have two different ragas with the same name?
4. The term 'Devangandharam' was taken only after finding that Dikshitar has used this word in his kriti 'Panchashat peetha roopini.' It is still a matter of contention whether that was a raga mudhra. Since the SSP (the last word on Dikshitar kritis and other issues for many) calls it only Devangandhari. Now it could be conveniently distinguished with two different names for the two ragas.
5. Now comes the term Karnataka Devagandhari - My take on this is that this was coined by Mysore Vasudevachar for his composition 'Bhajare bhaja manasa.' I cannot be sure about this but I remember people only referring to this song as Karnataka Devagandhari.
6. Since Bimpalas is a north indian raga it could be conveniently used for tukkadas and not kritis! So one found this being used to refer as the raga name for a song like say Vella tamarai.
Given this situation what can one call the raga I sang? I can call it Karnataka Devagandhari, Bimpalas or 'Xerox' Abheri if you like. The reason I choose to call it Abheri is that the most popular and well known song Nagumomu, sung in this exact same scale is referred to only as Abheri! Like Kamal Hassan said in the film Nayaka "Ask them to stop and I'll stop!" Let them stop calling the raga of the present day Nagumomu as Abheri and I'll do likewise.
Now let me present a different case and show that the parallel of what I have done is what the musical community has done over time. This is the case of the popular Pantuvarali. Almost 5 years ago I wrote and article on sangeetham.com asking "Is it really Pantuvarali?" I managed to hunt down that article and I am reproducing it below.
Pantuvarali is a fairly popular and well-known raga in Carnatic music. Just as G R Viswanath often went in "two down" in the Indian batting order, Pantuvarali has invariably been "one down" in a concert! That is the third piece after a varnam and a short, sharp piece.
But is the Pantuvarali that we commonly refer to the real Pantuvarali? A look at some of the historical facts surrounding this issue raises interesting questions. The common Pantuvarali that we all know is the 51st Melakarta - Kamavardhini. Now Kamavardhini found appearance only in the 19th century when the Kanakangi mela scheme was formed. Prior to that, this scale was always referred to only as Ramakriya. Also, as per the asampoorna mela paddhati, it was Kashiramakriya.
Now one proof that the current Kamavardhini was the old Ramakriya can be got from texts which give Dipakam as a janya of Ramakriya. The notes in Dipakam are exactly the 51st mela.
What happened to Ramakriya? Well Ramakriya, which has always been the 51st mela in the old texts, slowly got erased and replaced by Pantuvarali. For instance, some texts of Tyagaraja kritis give some songs as Ramakriya and some as Pantuvarali. 'Appa Rama bhakti' and 'Ennalu urage' are given as Pantuvarali whereas 'Vadera daivamu' and 'Shambho Mahadeva' are mentioned as Ramakriya.
Now coming to the other point in this whole issue. What was Pantuvarali? According to Venkatamakhi, Pantuvarali was the 45th mela or the current-day Shubhapantuvarali. According to the asampoorna mela paddhati, it was called Shivapantuvarali. So that probably explains 'Ennalu urage' being mentioned as Pantuvarali as it is sung predominantly as the current day 45th mela Shubhapantuvarali.
So, finally, we have a situation where Ramakriya has disappeared and become Kamavardhini. Pantuvarali has become Shubhapantuvarali. And Pantuvarali and Kamavardhini are the same today!