Could this be the reason??
Common RAM Sizes
If I remember correctly the original SIMMs came in 256KB, 512KB and 1MB packages and cost a small fortune. In the days of Windows 95 a computer would commonly have several 4MB or 8MB memory modules. By the time Windows 98 came out these had become 16MB or 32MB modules to make up around 64MB in a good system. For Windows XP computers 128MB is a workable minimum depending on what applications you want to run, modules tend to be 128MB, 256MB or 512MB. Currently systems routinely ship with 512MB sticks and 1GB sticks are becoming more common.
RAM module sizes always double: 4MB, 8MB, 16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1GB, 2GB, etc. (since strictly speaking 1GB = 1024MB) You wont find any 96MB RAM modules for example, but your system may have an "unusual" amount of total RAM for a couple of reasons
The system contains different sized RAM modules. For example your system shows 192MB of RAM. Most likely this was a system that started life with 64MB of SDRAM and was upgraded by adding a 128MB module.
The system has onboard video. When a system has onboard video the video 'card' is integrated into the motherboard, but no video memory is provided, instead the system reserves part of the system RAM to act as video memory. How much memory is reserved depends on settings in the BIOS and is usually any standard size from 4MB to 64MB. The 'total' amount of RAM that Windows sees is then the size of the RAM module, less the amount reserved for video. This can result in some very odd-looking amounts for total system RAM. For example a system's total RAM may be reported as 352MB. This could be made up of one 128MB module plus one 256MB module less 32MB reserved for video.