I've been underestimating you've been underestimating he's been underestimating we've been underestimating you've been underestimating they've been underestimating
I'd been underestimating you'd been underestimating he'd been underestimating we'd been underestimating you'd been underestimating they'd been underestimating
I'll be underestimating you'll be underestimating he'll be underestimating we'll be underestimating you'll be underestimating they'll be underestimating
Future perfect
I'll have underestimated you'll have underestimated he'll have underestimated we'll have underestimated you'll have underestimated they'll have underestimated
Future perfect continuous
I'll have been underestimating you'll have been underestimating he'll have been underestimating we'll have been underestimating you'll have been underestimating they'll have been underestimating
I'd be underestimating you'd be underestimating he'd be underestimating we'd be underestimating you'd be underestimating they'd be underestimating
Past
I'd have underestimated you'd have underestimated he'd have underestimated we'd have underestimated you'd have underestimated they'd have underestimated
Past continuous
I'd have been underestimating you'd have been underestimating he'd have been underestimating we'd have been underestimating you'd have been underestimating they'd have been underestimating