Suspense account in solo 401(k), how do I track this, if I do at all?

I have a company that over-contributed to my solo 401(k) one year, years ago. I'm now able to start doing employer contributions again, and they must be coming out of that suspense account before they come out of my normal funding accounts (bank accounts like checking). Note that I do NOT use payroll as I only write myself checks for member draws, + estimated taxes as scheduled.

I have not tracked the amount in that suspense account for years, 1) because it was not immediately available, meaning I'd have to call in to get the value, and 2) It was already considered and tracked as a contribution in my normal accounting flows: money came out of my bank and funded an employer contribution.

The amount in the suspense account can also fluctuate, because the holding company apparently keeps it invested in funds. But it should be growing tax free?

I would like to track that the company made a discretionary contribution, but I need the suspense account entered as an asset or account as the source of the funds. How do I set up the account and/or track the fluctuations in value without attributing increases to income and decreases to expenses? In reality, the money that's in there will get zeroed out and then the amounts above that threshold will be coming from my normal bank accounts.