When you are over 50, you get an additional allowance for the amount that you can contribute to 401k - in addition to the usual limit of $ 18500 (in 2018), you are allowed to contribute $ 6000 of 'catch-up' contribution.
Question: when contributing, does it matter at any time which part of the contribution is 'normal' and which part is 'catch-up'?
Aside from potential tool / input limitations at specific employers, do I have to specify and remember to which part I contributed what?
For example, when I contribute the whole catch-up in Jan, and then change employer in Jun, I wouldn't be allowed to declare more 'catch-up' at the new workplace, but just 'normal' contributions?
Or does the catch-up rule simply raise the personal annual limit, and the IRS doesn't care about the parts?