CTL Memory allocation : ctl_memory_area_allocate behaviour

We are using ctl_memory_area_allocate() to manage the memory allocations instead of malloc. We have referred the below link for the example,

Referred below link
http://www.rowleydownload.co.uk/arm/packages/libraries/libctl/html/index.htm?http://www.rowleydownload.co.uk/arm/packages/libraries/libctl/html/ctl_memory_areas.htm

It appears to work fine but I have one question about the behavior of ctl_memory_area_allocate(). 

"It is not allocating the subsequent memory allocations in the contiguous space even when the memory is available.  It is actually creating gaps in between which may create other problems"  

example : struct test mem[8];
sizeof(struct test) = 24 byte
total size of mem = 192 byte
--  First node allocation happens at same address as that of mem[0].

-- Second node allocation happens at the offset of 672 bytes.

Please clarify if the above behavior is normal. 

Best regards

Hemraj