Is there any significance to the difference in Godzilla's roar?

As soon (or late, for that matter) as Godzilla appears in full size in Hollywood's 2014 take on it, he utters a giant roar that seems to a large degree similar to his original roar from the Japanese movies finished with a very deep growling sound (that is also significantly featured in the trailer). And exactly this growling finish to his roar seems to add much to his gigantic presence and the awe-inspiring (for lack of a better term) atmosphere that accompanies him.

But at the end, when the supposedly dead Godzilla rises from the ashes of San Francisco and ventures into the ocean, effectively celebrated by the people (and the movie) for saving them (even if not their city ;-)) from the MUTOs, it is exactly this growling finish that I missed in his final "farewell roar". Now I certainly know that I'm absolutely splitting hairs here, but is there any significance to the fact that his last roar didn't feature this "growling finish" or is this a mere coincidence or mishearing on my part?

Best Answer

My take on the final roar is it is a farewell to the people of San Francisco, where as the ones at the beginning were more of an attack roar. He's a little ticked the MUTO's have forced him to come calling, so the attack roar. When he's leaving he just can't go away, so says goodbye.