Yes, you got it. TCG changed the text in order to prevent an FTK. In the OCG you can increase the ATK of Gandora-X and then do burn damage equal to its CURRENT atk not ORIGINAL.
I’m not here to tell you why there are differences between TCG and OCG, but to simply state that they exist. YGO Omega scripts two different versions of the same card when there is a text difference in these cases, so that the TCG players will use the legal TCG version of the card in ranked TCG.