The end result is the same but there are accounting considerations that would favor a merger over an acquisition or vice versa. From the Journal of Accountancy...
IN A MERGER, THE PARTIES NEGOTIATE how relative value will translate into the amount of ownership each party will have in the new company. In an acquisition, the parties negotiate how the relative value contributed to the new enterprise will translate into the purchase price.
TWO GOOD REASON FOR PARTIES TO MERGE rather than treat the combination as an acquisition are that a merger does not require cash and may in some cases be accomplished tax-free for both businesses.
TWO ADVANTAGES OF A STOCK ACQUISITION are that it’s a faster and easier transaction than an asset purchase and the buyer does not experience the dilution of ownership that occurs in a merger.
Nothing wrong with changing the deal due to the changing circumstances of the halt and/or new information they learn from their accountant. The important thing is that the merge is still on.