I have been working on signcryption scheme and its security proof. I want to compute the efficiency in terms of number of scalar multiplication operation, number of exponential operations, and number of bilinear pairing operation. I am comparing it with other schemes as well. I think I am missing out some information regarding point scalar multiplication and couldn't figure how should I count the number of multiplication operation. For example if U in the figure below, I see only 2 multiplication operations U1=r1P2 and U2=r1QA. Is it correct? For the reference, I am looking into Heterogeneous hybrid signcryption for multimessage and multi-receiver.
Presumably you are working from Heterogeneous hybrid signcryption for multi-message and multi-receiver by Niu et al (it would've been useful for you to include this information). In this case the value $sk_A$ is an element of $G_1$ and so all $n$ of the operations $S_i=(r_1+h_i)sk_A$ are also scalar multiplications.
This gives a total of $n+2$ scalar multiplications in $G_1$; $2n$ pairing computations at step 2, and $2n$ exponentiations in $G_2$ (also at step 2).