I've been underestimating you've been underestimating she's been underestimating we've been underestimating you've been underestimating they've been underestimating
I'd been underestimating you'd been underestimating she'd been underestimating we'd been underestimating you'd been underestimating they'd been underestimating
I'll be underestimating you'll be underestimating she'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 she'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 she'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 she'd be underestimating we'd be underestimating you'd be underestimating they'd be underestimating
Past
I'd have underestimated you'd have underestimated she'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 she'd have been underestimating we'd have been underestimating you'd have been underestimating they'd have been underestimating