“ I understand that these two accounts are defined contribution plans.”--->I guess it depends; when it comes to retirement plans, you could have a defined contribution or a defined benefit plan. If you have a 401k plan offer from your employer, this is not known as a defined benefit plan. Instead, you are actually using a defined contribution plan in which you and your employer put money into it.There are two types of Keogh plans, the defined contribution plan and the defined benefit plan. A Keogh plan can consist of separate defined contribution and defined benefit components.
“ I'm unclear, however, on if I should be treating these two accounts as one account to figure out my deduction limit or if I can take a deduction for the contributions made to the account with my new employer and an additional deduction for contributions to my self-employed plan?”----> Keogh plan can be established in addition to 401k/IRA accounts, but since a Keogh plan is a qualified plan, your contributions to your 401K/IRA(NOT R-401K/R-IRA,I mean) account may not be fully deductible. The amount that you can contribute to a Keogh depends on whether or not you are participating in other retirement plans. Additionally, as you work as an employee and participate in the employer's qualified plan under defined contribution plan, you can still have a Keogh plan if you have net earnings from self-employment. Your contributions are subject to the overall limitations for defined contribution plans or defined benefit plans. All of your contributions into any qualified plan are combined for purposes of the annual contribution limit. Keep in mind there may be eligibility, contribution, and income requirements associated with these types of accounts.