Tawaf after Asr is not only allowed, it is more virtuous because of the Barkat of the time after Fajr and after Asr. However, Tahiyyatut-tawaf should be delayed until after sunset or sunrise.
[quote]Assalāmu `alaikum Warahmatullāhi Wabrakatuh,
It is sunnat to perform the wājib two rakāts after tawāf immediately after the tawāf. To delay the wājib rakāts salāh aftertawāf is makrūh. (Mu`allimatul hujjaj, Pg 152, Idaratul Qur’aan)
However if it is the makrūh times of salah, for example sunrise, midday and sunset, then the two rakāts wājib salāh aftertawāf should be delayed until after the makrūh times.(ibid.)
You were correct to delay the two rakāts wājib salāh until after the maghrib salāh.
It would be better for you to have performed the two rakāt wājib salāh after the maghrib salāh and before the sunnats ofmaghrib salāh.
To perform the wājib salah after tawāf by the maqām Ibrahīm is desirable. (ibid)
However, preference will be given to performing the wājib salāh immediately after the maghrib salāh as that is sunnah.
In principle, a sunnat will be preferred over a Mustahab act. (ibid)
And Allah Ta'āla Knows Best,
Muftī Ebrahim Desai