about stacked wilds

Hi there,
I saw a slot game weeks ago,in the free game, the first reel of a screen for all free spin becomes all wilds. I am thinking the math for the similar feature. In this case, the first reel is all wild, so to estimate the winning line, the first reel could be any symbols appearing in the second reel of the screen. Does it mean the payout will be different if player bet and play at maximum lines or just one line? Here is my reason, if reel two of the second has K (top), Q (middle) and J (bottom), if we bet one line only (assuming a line across the top row) , the WILD on the first reel can only be K to make a win. But if we bet all lines, each WILD on the first reel could be K or Q or J so it will increase the chance to win. So does it mean in the feature when the whole first reel is WILD, betting at max line has more advantage?

The rtp will still be the same for each line. The hit frequency at max lines will be different since you will tend to have several wins at the same time.