Learn Farsi: ما درخواست شما را در طول ساعت‌های اداری از طریق این سامانه بررسی می‌کنیم. - We review your request during administrative hours via this system.

While dar simply means 'in', dar tul-e translates specifically to 'during' or 'throughout the length of'. It is a formal compound preposition that emphasizes the duration of time. Notice that it requires the invisible ezafe linking vowel to connect to the next word, making it dar tul-e sā'at-hā.

Could we use bā (with) instead of az tarigh-e for 'via this system'?

You could, but az tarigh-e is much more precise and formal. While bā generally means 'with' (like using a physical tool), az tarigh-e specifically means 'via', 'through', or 'by means of'. It is the preferred choice for administrative or technical mediums like networks, websites, and systems.

Why is the direct object marker rā placed after shomā instead of right after darkhāst (request)?

The direct object marker rā must always follow the complete noun phrase, not just the head noun. Here, the entire object being reviewed is 'your request' (darkhāst-e shomā), so rā is placed at the very end of that connected phrase.

There are two prepositional phrases here. Does it matter which one comes first?

In Farsi, expressions of time generally come before expressions of manner, medium, or place. This is why the duration phrase dar tul-e sā'at-hā-ye edāri comes before the medium phrase . Farsi is flexible, so swapping them isn't strictly wrong, but the current order sounds the most natural.