I have a Whirlpool wall oven (Model Nbr YRBS275PDQ7) that I would like to replace with a Bosch 800 Series 27" (Model Nbr HBN8451UC). The old cabinetry will not be changed and I am hoping that the existing cutout can be used. The width and depth requirements are the same as the new oven, but the height of the existing cutout is 0.5" larger than needed. Will this cause any issue with the installation? In particular, I am wondering if there would be any gap between the oven and cabinet. For reference, here are the dimensions:

Existing Cutout:
W = 25.5"
H = 27.5"
D = 24"

New Bosch Wall Oven Cutout Requirements:
W = 25.5"
H = 27"
D = 23.5"

I am also wondering whether or not I could install the 30" (Model Nbr HBL8451UC). This model requires the same height and depth requirements, but requires 28.5" for the width of the cutout. I have this available in the cabinet (if I make the cut 3" wider). Are there any other considerations before making this change? Thanks in advance for any replies!