The tax code ever multiplies in complexity. Where 401k catchup contribution was previously defined only by age, it now is defined by age & income. Over 150k puts you into a roth 401k after $24500. The lion kingdom, making below average income, will encounter the limit in 2 more pay periods. Most everyone else in the bay area has already encountered it. Betterment only allows defining fixed percentages to contribute to the roth & traditional in every pay period while the tax code only defines specific dollar amounts to contribute in the entire year. After the next pay period, the lion kingdom would have to change the setting to 55.56% in the roth 401k & 44.44% in the traditional 401k. In 2 pay periods, it would have to be changed to 100% roth. Then, presumably betterment would cap the roth so the total of the 2 didn't exceed $32,500. The settings would have to hit right between the pay periods & they change every year as the...