Yea its probably the HEAT barrage, iirc it does give a damage bonus. I know autofire is what everyone hates but this is just my opinion on how the pak howie can be changed to provide more leeway for axis players to get around it, I proposed changes to barrage because you would rarely if ever see a pak howie autofiring into someone's base, meanwhile I've had multiple games already where I get white phos and heat shells dropped in my base. Back on topic, other than a 380 MP investment, the opportunity cost of the pak howie is almost 0, you are neither giving up the chance to get a vehicle nor anti-tank capabilities. (Captain unlock comes with aa truck and AT gun.) Not to mention it costs 100 muni to get a double zook RE to ward off any scout car/ flame HT dives. It's easy to turtle for a few minutes to get it out and bam you're back on course with map control because any fights you take against infantry in cover is almost instant win.
I mean there are a lot of other indirect ways to fix this other than nerfing the pack howitzer directly.
E.g. Buff Ost healing so that aoe damage affects them lesser letting inf squads get back out on the field faster (change healing to aura) LOL JK DONT KILL ME PLEASE
Yes HEAT barrage does a lot more damage per shell but it's only 3 shells lul. Good against fortifications and stuff.
No offense, but if your issue is pack howies barraging your base constantly, then there's larger problems for you than just the pack howie. Base rape with anything feels frustrating and oppressive, but it's usually a sign that you've lost too much map control and he can just turtle around near enough to your base to be able to barrage it. That shouldn't be happening in an even game and it's, again, a sign that you've been losing the game as a whole, and not just that one unit is OP. The same thing could happen with leigs or mortars or mortar HTs. And turtling with midrange units against long range units isn't exactly "easy", especially without access to MGs.
Also, opportunity cost is there, as with all USF tier units because it's still a split-tier system. You can't have a pack howie and an MG without slowing down your teching or picking airborne. Not a huge issue, but saying it's zero is disingenuous and incorrect.