Seller Contract - Improvements Clause (Seller Financed)

[Aaron Natalie]

Seller included the following clause in the Improvements section of our contract (using Seller Financing):

Buyer shall keep the premises in good repair at their own expense during the life of this contract, and shall not make any changes or structural alternations to the premises without written consent of the seller. In the event all of the terms of this contract have been complied with, seller shall not unreasonably withhold such permission.

We do not intend to demolish or anything like that. Just general updates, possible new flooring...

Is this a normal clause? What do think any restrictions could be? It is combined commercial and residential property. Could he stop us from updating apartments? Commercial space?