portal frame design

[gtr35]

hey engtips family

i was checking a portal frame


/ \ 5º
/ | | | |
| | |

the rafter section tapers from outside column (≈ 2'0") to apex (≈ 4'0")
actually ive seen a few like this apex section deeper than at outside column

i was wondering your opinions on the benefit of using apex deeper design

also i havent modeled im trying to reason it out if the stiffer section would cause it
to behave more like a simply supported continuous

and the ends for lateral

thanks